Emulation of photonic synapses through photo‐recordable devices has aroused tremendous discussion owing to the low energy consumption, high parallel, and fault‐tolerance in artificial neuromorphic networks. Nonvolatile flash‐type photomemory with short photo‐programming time, long‐term storage, and linear plasticity becomes the most promising candidate. Nevertheless, the systematic studies of mechanism behind the charge transfer process in photomemory are limited. Herein, the physical properties of APbBr3 perovskite quantum dots (PQDs) on the photoresponsive characteristics of derived poly(3‐hexylthiophene‐2,5‐diyl) (P3HT)/PQDs‐based photomemory through facile A‐site substitution approach are explored. Benefitting from the lowest valance band maximum and longest exciton lifetime of FAPbBr3 quantum dot (FA‐QDs), P3HT/FA‐QDs‐derived photomemory not only exhibits shortest photoresponsive characteristic time compared to FA0.5Cs0.5PbBr3 quantum dots (Mix‐QDs) and CsPbBr3 quantum dots (Cs‐QDs) but also displays excellent ON/OFF current ratio of 2.2 upon an extremely short illumination duration of 1 ms. Moreover, the device not only achieves linear plasticity of synapses by optical potentiation and electric depression, but also successfully emulates the features of photon synaptic such as pair‐pulse facilitation, long‐term plasticity, and multiple spike‐dependent plasticity and exhibits extremely low energy consumption of 3 × 10−17 J per synaptic event. Engineering of minimum photo‐recording time in poly(3‐hexylthiophene)/APbBr3 perovskite quantum dots‐based photomemory via facile an A‐site substitution approach is demonstrated. poly(3‐hexylthiophene‐2,5‐diyl)/FAPbBr3 quantum dot‐derived photomemory displays an extremely short programming time of 1 ms and enables the extremely low energy consumption of 3 × 10−17 J per synaptic event on the application of photonic synapse.