A solar cell, characterized by comprising: an N-type substrate ; a P-type emitter formed on a first surface of the N-type substrate , wherein the P-type emitter comprises a first portion and a second portion , first pyramid structures are formed on a top surface of the first portion , and second pyramid structures are formed on a top surface of the second portion , wherein a transition surface is respectively formed on at least one edge of each first pyramid structure , the transition surface is joined with two adjacent inclined surfaces of the each first pyramid structure , and the transition surface is concave or convex relative to a center of the each first pyramid structure , wherein a substructure is formed on each of top surfaces of at least a part of the first pyramid structures , and a shape of the substructure is spherical or spherical-like, wherein edges of each second pyramid structure are straight, and wherein a sheet resistance of the first portion ranges from 10 ohm/sq to 500 ohm/sq, a doping concentration at the top surface of the first portion ranges from 1E 17 atoms/cm 3 to 8E 19 atoms/cm 3 , a sheet resistance of the second portion ranges from 100 ohm/sq to 1000 ohm/sq, and a doping concentration at the top surface of the second portion ranges from 1E 16 atoms/cm 3 to 5E 19 atoms/cm 3 ; a tunnel layer and a doped conductive layer sequentially formed over a second surface of the N-type substrate in a direction away from the N-type substrate ; and a first metal electrode formed on the first surface of the N-type substrate , wherein the first metal electrode is electrically connected to the first portion of the P-type emitter. an N-type substrate ; a P-type emitter formed on a first surface of the N-type substrate , wherein the P-type emitter comprises a first portion and a second portion , first pyramid structures are formed on a top surface of the first portion , and second pyramid structures are formed on a top surface of the second portion , wherein a transition surface is respectively formed on at least one edge of each first pyramid structure , the transition surface is joined with two adjacent inclined surfaces of the each first pyramid structure , and the transition surface is concave or convex relative to a center of the each first pyramid structure , wherein a substructure is formed on each of top surfaces of at least a part of the first pyramid structures , and a shape of the substructure is spherical or spherical-like, wherein edges of each second pyramid structure are straight, and wherein a sheet resistance of the first portion ranges from 10 ohm/sq to 500 ohm/sq, a doping concentration at the top surface of the first portion ranges from 1E 17 atoms/cm 3 to 8E 19 atoms/cm 3 , a sheet resistance of the second portion ranges from 100 ohm/sq to 1000 ohm/sq, and a doping concentration at the top surface of the second portion ranges from 1E 16 atoms/cm 3 to 5E 19 atoms/cm 3 ; a tunnel layer and a doped conductive layer sequentially formed over a second surface of the N-type substrate in a direction away from the N-type substrate ; and a first metal electrode formed on the first surface of the N-type substrate , wherein the first metal electrode is electrically connected to the first portion of the P-type emitter. <EOS>