In recent years, the number of depression patients in China has been increasing rapidly. This surge is alarming and calls for a multifaceted approach to address the issue. A large number of clinical research results have shown that environmental factors have an important impact on the psychological state and recovery efficiency of patients with depression. These factors can influence mood, cognitive function, and overall well-being. However, despite the growing recognition of the importance of environmental influences on mental health, there is currently a lack of relevant research from the perspective of architecture, especially research results on the environmental perception of patients with depression. This gap in knowledge limits our ability to design spaces that are truly supportive of the needs of individuals with depression. Therefore, a comprehensive study using the grounded theory research method was undertook, including semi-structured interviews with 33 depression patients. Our goal was to establish a theoretical model of environmental perception for patients with depression.The grounded theory approach allowed us to explore the lived experiences of individuals with depression in depth and derive meaningful insights from their perspectives. Through this method, the study was able to identify common themes and patterns in how patients perceive their environments. Through the Nvivo 12 plus software, the interview content was encoded and analyzed to construct a theoretical model. This model covers three main categories: physical elements, spatial elements, and environmental elements. These categories were further broken down into ten subcategories and 22 specific concepts, providing a detailed framework for analysis. Specifically, the physical elements category includes factors such as lighting, noise levels, and temperature, which can directly affect a person’s comfort and mood. The spatial elements category encompasses aspects like room size, layout, and the presence of private or communal spaces. The environmental elements category considers the broader context, such as the presence of natural features, access to outdoor spaces, and the overall atmosphere of the environment. To more accurately reflect the attention and perception differences of patients with different degrees of depression to environmental elements, the study used the TOPSIS comprehensive evaluation method to optimize the research results. By applying this method, the study was able to quantify and compare the varying levels of environmental perception among patients with mild, moderate, and severe depression. This allowed to identify which environmental factors were most critical for each group and how they could be addressed in architectural design.The research results show several important findings. Firstly, depression patients are characterized by an overall dullness in environmental perception, coupled with increased sensitivity to specific environmental elements. This means that while some sensory inputs may be less noticeable to them, others can be overwhelmingly intense. Specifically, with the increase of the degree of depression, patients’ sensitivity to noise and strong light increases significantly. For example, patients with severe depression may find even moderate levels of background noise extremely distracting and distressing. Secondly, patients with higher degrees of depression have a stronger needfor a sense of security and privacy in space. They tend to prefer closed space characteristics, such as rooms with fewer windows or higher walls, which can provide a sense of enclosure and protection. This preference may stem from a desire to feel safe and sheltered from external stressors. In contrast, patients with mild or moderate depression may be more open to environments that offer a balance between privacy and openness. Thirdly, patients with mild and moderate depression pay more attention to natural landscapes. They often report feeling more relaxed and positive in environments that incorporate natural elements, such as views of green spaces, water features, or access to outdoor areas. However, the perception of landscape environment of patients with severe depression decreases sharply. They may feel disconnected from their surroundings and have difficulty deriving comfort or pleasure from natural settings. Based on the environmental perception characteristics of depression patients, the study proposes differentiated environmental design suggestions for patients with different degrees of depression from three aspects: reducing environmental stimulation, improving environmental privacy, and increasing landscape naturalness. For patients with severe depression, it is crucial to minimize environmental stimuli that can cause distress, such as excessive noise or harsh lighting. Creating spaces with soft, diffused lighting and sound-absorbing materials can help create a calming atmosphere. For all patients, but especially those with moderate to severe depression, ensuring that spaces offer a sense of privacy and security is essential. This can be achieved through thoughtful layout design and the use of partitions or other barriers to create secluded areas. Finally, incorporating natural elements into the design can benefit patients with mild to moderate depression. This can be done through the use of indoor plants, natural materials, and views of outdoor green spaces. The research results not only enrich the theoretical research on the environmental perception elements of patients with depression but also provide references for the design practice of healthcare buildings. By understanding how different environmental factors affect patients with varying degrees of depression, architects and designers can create spaces that support mental recovery and well-being. Future research may explore the environmental perception characteristics of patients with severe depression and the long-term impact of environmental design on their recovery. This could involve longitudinal studies that track patients’ responses to specific environmental interventions over time, as well as exploring how individual differences, such as age, gender, and cultural background, might influence environmental perception and preferences. Additionally, future work could investigate the potential benefits of incorporating advanced technologies, such as smart lighting systems or personalized environmental controls, into the design of therapeutic spaces.