A solar gas turbine power generation system based on a photothermal principle, comprising: a gas turbine, a solar collector and a solar reflector; the gas turbine is fixed above the solar reflector through a fixing rod, the gas turbine comprises a compressor, a turbine, a recuperator and a combustion chamber; the solar collector comprises an absorber plate; and the absorber plate is located on a reflecting focus or a focal line of the solar reflector, characterized in that the recuperator comprises an outer shell, an intermediate shell and an inner shell, wherein a low-temperature gas inlet passage is formed between the intermediate shell and the outer shell, a high-temperature gas inlet passage is formed between the intermediate shell and the inner shell, an inlet and an outlet of the low-temperature gas inlet passage communicate with an outlet of the compressor and an inlet of the combustion chamber, respectively, and an inlet and an outlet of the high-temperature gas inlet passage communicate with an outlet of the turbine and an outside, respectively; and the absorber plate covers the outer shell of the recuperator; wherein the SGT power generation system comprises a mounting stand; the solar reflector is provided on the mounting stand through an adjustment device, and the adjustment device comprises telescopic rods, hinges, bases, expansion bottles and tubes; an even number of bases are fixed on a top of the mounting stand, the bases are provided and arranged pairwise and symmetrically, the bases are connected to the telescopic rods through the hinges, and the telescopic rods are connected to a bottom of the solar reflector; and the expansion bottles are fixed outside each of the bases and on the top of the mounting stand, the expansion bottles are connected to the telescopic rods of the bases on an opposite side through the tubes, and when the expansion bottles are heated, the telescopic rods on the opposite side are stretched out to raise the solar reflector on the opposite side. the gas turbine is fixed above the solar reflector through a fixing rod, the gas turbine comprises a compressor, a turbine, a recuperator and a combustion chamber; the solar collector comprises an absorber plate; and the absorber plate is located on a reflecting focus or a focal line of the solar reflector, characterized in that the recuperator comprises an outer shell, an intermediate shell and an inner shell, wherein a low-temperature gas inlet passage is formed between the intermediate shell and the outer shell, a high-temperature gas inlet passage is formed between the intermediate shell and the inner shell, an inlet and an outlet of the low-temperature gas inlet passage communicate with an outlet of the compressor and an inlet of the combustion chamber, respectively, and an inlet and an outlet of the high-temperature gas inlet passage communicate with an outlet of the turbine and an outside, respectively; and the absorber plate covers the outer shell of the recuperator; wherein the SGT power generation system comprises a mounting stand; the solar reflector is provided on the mounting stand through an adjustment device, and the adjustment device comprises telescopic rods, hinges, bases, expansion bottles and tubes; an even number of bases are fixed on a top of the mounting stand, the bases are provided and arranged pairwise and symmetrically, the bases are connected to the telescopic rods through the hinges, and the telescopic rods are connected to a bottom of the solar reflector; and the expansion bottles are fixed outside each of the bases and on the top of the mounting stand, the expansion bottles are connected to the telescopic rods of the bases on an opposite side through the tubes, and when the expansion bottles are heated, the telescopic rods on the opposite side are stretched out to raise the solar reflector on the opposite side.