The invention discloses a method of preparing a perovskite solar cell by using SrGeO3 as an electron transport layer. The method comprises the following steps: (1) an FTO transparent conductive glasssubstrate is cleaned and dried and is then subjected to ultraviolet light and ozone treatment, spin coating of an SrGeO3 electron transport layer on the treated FTO transparent conductive glass substrate is then carried out, and putting on a heating table for heating treatment is carried out; (2) a perovskite film layer is prepared on the SrGeO3 electron transport layer in the first step; (3) a hole transport layer is prepared on the perovskite film layer prepared in the second step; and (4) MoO3 and an Ag electrode are prepared. The SrGeO3 is used as the electron transport layer, higher photoelectric conversion efficiency is obtained, the surface of the film is smoother, the film can be used as a good substrate for subsequent perovskite layer deposition and growth, crystallization of theperovskite film is more uniform and dense, the process is simple and convenient, the preparation difficulty is low, and the device performance is stable.