According to the theory of the stereo mapping based on three-line, the simulation of three-line satellite images for cloud-top height retrieval is presented. The matching method SIFT was improved, and the cloud top height was retrieved by the improved SIFT and forward intersection. The correctness of the simulated three-line satellite images was verified and a new way was explored to retrieve the cloud top height in low light condition at night. Finally, the sources of the errors in the cloud top height were analyzed in detail. A new method was given to eliminate the error caused by cloud motion.