Perovskite solar cells (PSCs) with CH3NH3PbX3 (MAPbX3, X=Br, I, Cl) as light-absorbing layer are used as a new generation of low-cost, high-efficiency photovoltaic devices. Compared with other types of photovoltaic devices, this type of cell has the advantages of abundant raw materials, simple process, etc., and its efficiency has risen rapidly from 3.8% to 25.7% in less than 15 years. It is almost comparable to commercial silicon solar cells and has become a new star in the field of energy applications. Normally, zinc oxide (ZnO) has been widely studied as the most important electron transport layer (ETL) of PSCs because of its advantages such as easy processed, high electron mobility, low manufacturing cost, and diverse morphology and structure. In this paper, ETL of ZnO nano film with different structures is taken as the research object, and its application in PSCs is summarized. The research progress of PSCs based on different morphology ZnO nano structures is introduced in detail, and the main problems faced by this type of solar cells are analyzed. In addition, the development trend of this device is proposed.