With the increasing attention focused on the measurement accuracy of the high altitude air temperature,it is necessary to research into the source of the radiosonde temperature sensor error.Solar radiation makes the most significant contribution to the error in upper air temperature measurement.A computational fluid dynamics(CFD) method is employed to study the errors induced by solar radiation and lead angles,from sea level to 32 km altitude.The results show that lead angle and solar incident angle are important factors that affect the errors.Simulation results can be used as a reference for error correcting,which has a potential to improve the measuring accuracy.