AbstractRoom‐temperature phosphorescence (RTP) two‐dimensional (2D) organic‐inorganic hybrid perovskites (OIHPs) that possess superior stability and efficient triplet energy transfer between inorganic parts and organic cations have been seen as promising materials in optoelectronic devices. However, the development of RTP 2D OIHP‐based photomemory has not been explored yet. In this work, the spatially addressable RTP 2D OIHPs‐based nonvolatile flash photomemory is first investigated to explore the function of triplet excitons in elevating the performance of photomemory. Thanks to the triplet excitons generated in RTP 2D OIHP, extremely low photo‐programming time of 0.7 ms, multilevel behavior of minimum 7 bits (128 levels), remarkable photoresponsivity of 19.10 AW−1and significantly low power consumption of 6.79 × 10−8J per bit can be achieved. The current study provides a new prospective in understanding triplet excitons function in nonvolatile photomemory.