Turpan basin located in Xinjiang Uygur Autonomous Region experiences the extreme dry and hot climates with the maximum outdoor air temperature of 38 °C and average annual precipitation of 16.6 mm. The problems of poor indoor thermal comfort, high energy consumption and fragile ecological environment are particularly prominent in this region. To improve indoor thermal comfort and reduce cooling energy demand, the passive cooling strategies adapted to this region should be investigated and then the effect of building design parameters on indoor thermal environment in summer should be analyzed. Unfortunately, the study focusing on the passive cooling strategies and critical design parameters for residential buildings in Turpan basin is limited, which restricts the development of modern building with low energy consumption and advanced energy saving technologies.A traditional rural dwelling located in Turpan basin was selected for a field measurement in this study. The studied building was constructed using earth bricks and reinforced with concrete beams and columns. The field measurement was conducted from Jul. 1 to Jul. 4, 2022 to investigate indoor thermal environment and evaluate thermal performance of the studied building in summer with the extreme dry and hot climate conditions. Through the comparative studies on indoor thermal environment for different rooms were performed, the significant effects of building orientation and semi-underground space on indoor thermal condition were determined. In detail, the higher indoor temperature of south-facing room was caused by the huge heat gain from direct solar radiation through south-facing windows during the daytime, and sun-shade of south-facing window is an effective cooling strategy to protect indoor environment from intensive solar radiation. Additionally, the average inner surface temperature of walls of south-facing bedroom on semi-underground floor is 8.01 °C lower than that of south-facing bedroom on the ground floor. This phenomenon indicated that massive earth walls under ground provide natural cooling capacity for ensuring indoor thermal stability.The traditional rural dwellings in Turpan basin are characterized by air-drying shelter. For the selected building in this study, air-drying shelter was positioned on the roof of kitchen and it also was the most visible difference between north-facing bedroom on the ground floor and kitchen. To investigate the thermal regulation of air-drying shelter, the indoor thermal conditions of kitchen and north-facing bedroom were compared: the average and maximum indoor temperature of kitchen were 2.56 °C and 2.4 °C lower than those of north-facing bedroom on the ground floor. Then, the surface temperature of two rooms’ roofs were measured and the results indicated that the average inner surface temperature of kitchen’s roof is 2.64 ° C lower than that of north-facing bedroom on the ground floor. The air-drying shelter positioned on the roof of kitchen provided shading and natural ventilation to reduce solar heat gain of kitchen’s roof and increase the heat convection between the outer surface of kitchen’s roof and outdoor environment. Based on the characteristics of selected building, a numerical building model was developed in this study and was calculated using themeasured values of outdoor climate condition. The simulated results of indoor temperature were compared with the measured results, in order to evaluate the accuracy of the developed building model. The verified building model was used to investigate the design parameters, such as window shading form, shading projection coefficient, solar radiation absorption coefficient, floor numbers inside air-drying shelter and area ratio of hole to wall for air-drying shelter’s hollowed walls on indoor environment. The simulated results showed that shading projection coefficient of horizontal shading element and solar radiation absorption coefficient of envelops are the key cooling design parameters of traditional dwelling in Turpan basin. With shading projection coefficient increased from 0.2 to 0.4, the mean and maximum value of indoor air temperature decreasd by 0.53 and 1.01 oC. When solar radiation absorption coefficient of westfacing wall increased from 0.52 to 0.86, the maximum indoor air temperature increased by 0.67 °C.To evaluate the improvement of indoor thermal comfort caused by building design optimization, the optimal values of above-mentioned parameters were set up as follows: shading projection coefficient of horizontal shading element was 0.4, solar radiation absorption coefficient was 0.52, number of air-drying shelter space levels was Two and area ratio of hole to wall for the hollowed walls was 10 %. The indoor air temperature of the optimal building model was numerical calculated and the simulated results showed that the average and maximum indoor temperature of south-facing bedroom on the ground floor decrease by 3.19 °C and 4.36 °C, respectively. An obvious improvement of indoor thermal comfort could be observed in this study.