In recent years, flexible photodetectors (FPDs) have received increasing attention due to their applications in electronic eyes, flexible sensing, terminal devices, and wearable devices. In addition, metallic halide perovskite materials are considered as future materials for FPDs due to their compatibility with flexible substrates, low cost, simple synthesis methods, and superior optoelectronic properties. This review provides a comprehensive overview of the relevant cutting-edge research in the field of flexible perovskite photodetectors (FPPDs) from 2020 to 2022. First, the evaluation criteria for FPPDs are discussed and the development of perovskite stability criteria is emphatically described. Afterwards, the synthesis methods and device construction processes of metal halide perovskite materials commonly used by researchers in the past three years were described. These include single crystals and low-dimensional materials. Moreover, we have elaborated on the research of self-powered FPPD and its contributions in wearability, terminals, and portability. Finally, a summary of developments and possibilities in the field of FPPDs from 2020 to 2022 is provided.