Low-altitude economy, as an emerging industrial form and representative of new quality productive forces, is reshaping urban spatial structures through technological innovation and industrial integration. This paper systematically explains the theoretical relationship between low-altitude economy and smart city renewal from the perspectives of connotation analysis and development history, and deeply analyzes the profound impact of low-altitude economy on urban planning, transportation systems, and management models by combining practical cases from cities like Shenzhen and Hangzhou. The low-altitude economy utilizes airspace below 3, 000 meters as its carrier, achieving airborne flow of production factors through vehicles such as general aircraft, drones, and electric vertical take-off and landing (eVTOL) aircraft. Its development has passed through a germination period (2000-2015), a growth period (2016-2022), and an explosive period (2023-present). With continuous promotion by national policies, it has become a national strategic emerging industry and has been emphasized in government work reports, highlighting its significant status in economic development. Smart city renewal relies on digital technologies to dynamically optimize urban physical space and social systems, with core features including spatial reconstruction and governance upgrading. The low-altitude economy breaks through the physical boundaries of urban renewal through airspace resource development, while smart technologies provide a supporting platform for the integration of low-altitude systems. This theoretical coupling offers new ideas for the development of smart cities. As a representative of the low-altitude economy, eVTOL demonstrates great potential in urban transportation, logistics, emergency response, and other fields due to its zero emissions, low noise, and high efficiency. For instance, cities like Shenzhen and Hangzhou are building air transportation networks with eVTOL to achieve multi-modal transport coordination and enhance regional economic linkage efficiency. Simultaneously, eVTOL has promoted innovation in low-altitude logistics systems, systematically solving the "last mile" problem through spatial dimension elevation and intelligent coordination.However, the involvement of lowaltitude economy in urban renewal also faces challenges such as management mechanisms, management capabilities, technical difficulties, and service facilities. To address these, this paper proposes countermeasures including hierarchical infrastructure planning, dynamic airspace management zoning, and coordinated policy innovation, aiming to optimize spatial resource allocation, improve transportation efficiency, and promote sustainable urban development. Specifically, it recommends incorporating eVTOL take-off and landing platforms and charging facilities into urban planning to construct a three-dimensional transportation network; formulating unified and standardized low-altitude transportation management policies to clarify access thresholds, flight rules, and regulatory responsibilities; strengthening research and innovation in key technologies such as batteries and autonomous driving to improve the performance and safety of eVTOL; and building a comprehensive safety protection system to enhance public awareness and acceptance of eVTOL. In conclusion, through technological innovation and industrial integration, the low-altitude economy provides new solutions and development paths for smart city construction. With continuous technological progress and gradual policy improvement, it is expected to become an important component of urban transportation, driving cities toward a more intelligent, efficient, and livable development stage.