With the rapid development of domestic urban construction, there are more and more high-level and high-rise buildings.The problem of lighting right blocked by buildings becomes serious.In the planning management, how to reasonably define sunlight overshaded range and balance the interests of the developer and the surrounding residents are difficult problems for the planning management departments at various levels.Combining the national and local standards, and based on the actual working conditions, the paper discusses how to define the reasonable overshadowed range in sunlight calculation, which has reference significance to planning and management departments of all levels.