A 3D vertical structure photodetector and its manufacturing method were presented. The lower electrode of the photoelectric detector chip was welded to the substrate, and the upper electrode was connected to the amplifying circuit through the gold wire, so that the light could entere into the intrinsic layer through the side, which effectively solved the problem of heavy doping dead zone and metal electrode blocking light, reduced the light loss, reduced the composite rate, and improved the response degree. The structure of the junction in the semiconductor reduced the surface leakage current and increased the reverse breakdown voltage. The main part of the junction area was the parallel plane junction area, which effectively reduced the total junction capacitance area, reduced the parasitic time constant, and improved the response speed.