A storage unit and a manufacturing method therefor, and a three-dimensional memory, the storage unit comprising: a first conductivity type substrate; a trench layer stacked on the first conductivity type substrate along a first direction; a second conductivity type conduction layer, comprising a first part and second part passing therethrough, the first part being interposed between the first conductivity type substrate and the trench layer, and the second part being formed in a through hole penetrating the trench layer; a trench channel layer, passing through the trench layer and the first part of the second conductivity type conduction layer along a negative direction to the first direction and extending into the inside of the first conductivity type substrate; and an insulating layer positioned in the trench layer and surrounding the periphery of the trench channel layer; the first conductivity type substrate and the second conductivity type conduction layer respectively provide the carriers needed for read and erase operations. Good conduction can be implemented regardless of how the number of stacked layers of the memory cell increases, and is not affected by the processing problems caused by the continuous increase of the three-dimensional memory.