A back contact structure of a solar cell, the back contact structure comprising: a silicon substrate, the silicon substrate comprising a back surface comprising a plurality of recesses disposed at intervals, and a plurality of protrusion portions each disposed between two adjacent of the plurality of recesses; a plurality of first conductive regions and a plurality of second conductive regions disposed alternately in the plurality of recesses, wherein each first conductive region comprises a first dielectric layer and a first doped region which are disposed successively in the plurality of recesses, and each second conductive region comprises a second doped region; a second dielectric layer disposed between the plurality of first conductive regions and the plurality of second conductive regions, wherein the second dielectric layer is at least one in number; and a conductive layer disposed on the plurality of first conductive regions and the plurality of second conductive regions; wherein: the plurality of first conductive regions is a P-type doped region, and the plurality of second conductive regions is an N-type doped layer; or the plurality of first conductive regions is an N-type doped region, and the plurality of second conductive regions is a P-type doped layer; characterized in that: in two adjacent recesses, the second doped region of the second conductive region is a doped layer located at the bottom of one of the two adjacent recesses and the silicon substrate at the bottom of the recess is partially diffused for forming the doped layer; and the first conductive region is grown inside the other recess through deposition; and the first doped regions and the second doped regions do not extend to part of the regions between the recesses, such that the protrusion regions between the recesses can achieve separation between the first conductive regions and the second conductive regions. a silicon substrate, the silicon substrate comprising a back surface comprising a plurality of recesses disposed at intervals, and a plurality of protrusion portions each disposed between two adjacent of the plurality of recesses; a plurality of first conductive regions and a plurality of second conductive regions disposed alternately in the plurality of recesses, wherein each first conductive region comprises a first dielectric layer and a first doped region which are disposed successively in the plurality of recesses, and each second conductive region comprises a second doped region; a second dielectric layer disposed between the plurality of first conductive regions and the plurality of second conductive regions, wherein the second dielectric layer is at least one in number; and a conductive layer disposed on the plurality of first conductive regions and the plurality of second conductive regions; in two adjacent recesses, the second doped region of the second conductive region is a doped layer located at the bottom of one of the two adjacent recesses and the silicon substrate at the bottom of the recess is partially diffused for forming the doped layer; and the first conductive region is grown inside the other recess through deposition; and the first doped regions and the second doped regions do not extend to part of the regions between the recesses, such that the protrusion regions between the recesses can achieve separation between the first conductive regions and the second conductive regions.