Nonlinear　characteristics　are　essential　for　neuromorphic　devices　to　process　high-dimensional　and　unstructured　data.　However,　enabling　a　device　to　realize　a　nonlinear　response　under　the　same　stimulation　condition　is　challenging　as　this　involves　two　opposing　processes:　simultaneous　charge　accumulation　and　recombination.　In　this　study,　a　hybrid　transistor　based　on　a　mixed-halide　perovskite　was　fabricated　to　achieve　dynamic　nonlinear　changes　in　synaptic　plasticity.　The　utilization　of　a　light-induced　mixed-bandgap　structure　within　the　mixed　perovskite　film　has　been　demonstrated　to　increase　the　recombination　paths　of　photogenerated　carriers　of　the　hybrid　film,　thereby　promoting　the　formation　of　nonlinear　signals　in　the　device.　The　constructed　heterojunction　optoelectronic　synaptic　transistor,　formed　by　combining　a　mixed-halide　perovskite　with　a　p-type　semiconductor,　generates　dynamic　nonlinear　decay　responses　under　400　nm　light　pulses　with　an　intensity　as　low　as　0.02　mW/cm2.　Furthermore,　it　has　been　demonstrated　that　nonlinear　photocurrent　growth　can　be　achieved　under　650　nm　light　pulses.　It　is　important　to　note　that　this　novel　nonlinear　response　is　characterized　by　its　dynamism.　These　improvements　provide　a　novel　method　for　expanding　the　modulation　capability　of　optoelectronic　synaptic　devices　for　synaptic　plasticity.　©　2025　by　the　authors.