In　this　manuscript,　a　solution-processed　n-type　organic　phototransistor　based　on　vertical　structure　thin-film　transistors　was　proposed.　Due　to　the　vertical　structure　and　short　channel　length　(≈130　nm),　the　transistors　exhibited　excellent　current　density　(15.4　mA/cm2)　with　high　Ion/Ioff　ratio　(up　to　105).　On　account　of　this　structure,　the　face-on　π-π　stacking　of　P(NDI2OD-T2)　was　aligned　with　the　charge　transport　direction,　which　facilitated　charge　transfer　from　source　to　drain　electrode.　Moreover,　n-type　organic　phototransistors　based　on　vertical　thin-film　transistors　were　demonstrated　for　the　first　time,　in　which　the　active　layer　was　protected　by　the　source-drain　electrodes,　resulting　in　the　improvement　of　the　stability　of　the　device.　Due　to　the　nanoscale　channel,　efficient　separation　of　electron-hole　pairs　and　quick　charge　transfer　can　be　achieved.　Hence,　high-performance　n-type　phototransistor　was　obtained　with　responsivity　of　34.8　A/W,　photosensitivity　of　4.78　×　104,　detectivity　of　3.95　×　1013　Jones　and　external　quantum　efficiency　up　to　1.1　×　104%　under　400　nm　illumination　with　a　light　intensity　of　200　μW　cm−2,　which　was　much　better　than　those　reported　n-type　organic　phototransistors.　This　work　provided　a　strategy　for　the　fabrication　of　high　performance　n-type　organic　phototransistor,　which　paved　the　way　for　its　future　application　in　the　next-generation　organic　optoelectronics.　©　2019　Elsevier　B.V.