Since its discovery, perovskite has experienced tremendous development. Furthermore, due to the outstanding stability of two-dimensional (2D) perovskites, they have been attracting increasing attention. A reduction in the dimensions of perovskites and the introduction of long organic chains yield new structures and properties. As an emerging semiconductor material with high stability, 2D perovskites have many applications in the field of optoelectronics. This review mainly describes the development and application of 2D perovskites in recent years. Firstly, we introduce the basic structure and classification of 2D perovskites. Also, we discuss the change in their characteristics and performances with a variation in the number of inorganic layers. Next, 2D perovskites are classified according to their applications in different fields. Finally, a summary and outlook based on the current development trends of 2D perovskites are presented.