The invention discloses a preparation method for a P-type full-contact passivation solar cell, which can eliminate the phenomenon of front surface winding plating of a back surface oxide thin layer and a polycrystalline silicon or amorphous silicon thin layer. The preparation method sequentially comprises the following steps of: A, texturing a P-type silicon wafer and etching and polishing the back surface of the textured silicon wafer, B, preparing an oxide thin layer on the back surface of the silicon wafer and preparing a polycrystalline silicon or amorphous silicon thin layer on the oxidethin layer, C, performing boron doping on the polycrystalline silicon or amorphous silicon thin layer, D, removing borosilicate glass and winding plate of the oxide thin layer on the front surface ofthe silicon wafer and the polycrystalline silicon or amorphous silicon thin layer by etching liquid in a manner in which the back surface of the silicon wafer is upward, E, preparing a silicon nitridelayer on the doped polycrystalline silicon thin layer on the back surface of the silicon wafer, F, performing acid pickling on the front surface of the silicon wafer, then performing texturing again,and performing phosphorus doping, G, performing thermal oxidation on the front face of the silicon wafer after the phosphorosilicate glass is removed through acid pickling, H, plating a silicon nitride layer on the front surface of the silicon wafer, and I, preparing an electrode.