In the process of designing and adjusting the solar simulator, the side lobe effect and aberration of the optical integrator affect the irradiation uniformity, an integrating sphere is proposed to replace the optical integrator for uniform light and the compound parabolic reflector for beam shaping. First, based on the equal illuminance theorem and the radiation transfer theory, the calculation formula of the energy transmission efficiency of the porous integrating sphere is derived; Then, the light hole illuminance interference factor is introduced, and the effects of the aperture size of the integrating sphere, the radius of the integrating sphere, and the size and position of the baffle on the energy transmission efficiency and irradiation uniformity are analyzed. Finally, an integrating sphere uniform light system with high energy transmission efficiency and uniformity is designed and simulated with LightTools software. The simulation results show that: the average difference of irradiation uniformity and the range difference of irradiation uniformity are closest to 1 in the area where the ratio of the opening size and radius of the integrating sphere is 36%-40%, and the light is evenly distributed; When the baffle position is 0.8 times of integrating sphere radius away from the light entrance hole, irradiation non-uniformity at the outlet hole is 1.99%, which is the best position of the baffle; In the effective irradiation surface of Φ1032 mm, the irradiation non-uniformity is 1.98%, and the maximum irradiance is 0.62 solar constants, the spot simulation with high irradiation uniformity on large irradiation surface is realized.