Abstract: Temperature is an important load in the design and construction process of large-span spatial structures, and a temperature field is generally non-uniform due to the complexity of solar radiation and the occlusion relationship between structural members. Based on blanking algorithm, a special method is realized to calculate the sunlight shadow of round section members, and the solar radiation calculation program capable of considering geographic and weather information is developed. Taking the steel space truss of Beijing Daxing International Airport as an example, the transient temperature field of the structure is simulated using the thermal analysis module of ANSYS software, and several important solution conditions are discussed. The results show that:the temperature field in the large-span spatial structure shows obvious non-uniformity and time-varying characteristics after considering solar radiation, and the sunlight shadow should not be ignored. For large-span spatial structures which are relatively complex, the simulation method of temperature field proposed provides an important basis for the accurate simulation of the construction process.