A method for preparing a selective emitter solar cell, comprising: etching first regions and second regions of a surface of a semiconductor substrate, to form a textured surface with a plurality of protrusions on the first regions and the second regions of the surface of the semiconductor substrate, wherein each of the plurality of protrusions has a cross-sectional shape of trapezoidal or trapezoid-like in a thickness direction of the semiconductor substrate; characterized by further comprising: performing a diffusion treatment on at least part of the plurality of protrusions to form a first doped layer, and forming a first oxide layer above the first regions, wherein the first doped layer comprises a P-type doping element or an N-type doping element; re-etching the surface of the semiconductor substrate by using the first oxide layer as a mask, to etch each of the plurality of protrusions on the second regions to form a pyramid structure, such that the first doped layer on the second regions is etched to form a second doped layer with a doping concentration lower than a doping concentration of the first doped layer; and removing the first oxide layer to retain the first doped layer on the first regions, and providing the selective emitter including the first doped layer on the first regions and the second doped layer on the second regions. etching first regions and second regions of a surface of a semiconductor substrate, to form a textured surface with a plurality of protrusions on the first regions and the second regions of the surface of the semiconductor substrate, wherein each of the plurality of protrusions has a cross-sectional shape of trapezoidal or trapezoid-like in a thickness direction of the semiconductor substrate; characterized by further comprising: performing a diffusion treatment on at least part of the plurality of protrusions to form a first doped layer, and forming a first oxide layer above the first regions, wherein the first doped layer comprises a P-type doping element or an N-type doping element; re-etching the surface of the semiconductor substrate by using the first oxide layer as a mask, to etch each of the plurality of protrusions on the second regions to form a pyramid structure, such that the first doped layer on the second regions is etched to form a second doped layer with a doping concentration lower than a doping concentration of the first doped layer; and removing the first oxide layer to retain the first doped layer on the first regions, and providing the selective emitter including the first doped layer on the first regions and the second doped layer on the second regions. performing a diffusion treatment on at least part of the plurality of protrusions to form a first doped layer, and forming a first oxide layer above the first regions, wherein the first doped layer comprises a P-type doping element or an N-type doping element; re-etching the surface of the semiconductor substrate by using the first oxide layer as a mask, to etch each of the plurality of protrusions on the second regions to form a pyramid structure, such that the first doped layer on the second regions is etched to form a second doped layer with a doping concentration lower than a doping concentration of the first doped layer; and removing the first oxide layer to retain the first doped layer on the first regions, and providing the selective emitter including the first doped layer on the first regions and the second doped layer on the second regions.