In order to solve the problem that complex terrain has a great impact on spaceborne synthetic aperture radar (SAR) imaging, an estimation method of satellite imaging duration considering the terrain parameters of the target area is proposed. Simulation analysis is carried out by using 3D simulation software, and the simulation analysis of the influence of terrain factors on radar imaging in target area is realized by programming. The results show that this method can effectively improve the accuracy of spaceborne SAR imaging duration calculation, and provide an important basis for optimizing target imaging and orbit adjustment design.