The invention relates to a solar energy semicircular cavity dual-pipe heat collector, particularly to a solar energy heat collector which is suitable for solar energy groove-type paraboloid focusing. The heat collector comprises a flange 1, a light inlet 2, an outer pipe 3, an inner pipe 4, a heat insulation layer 5, a partition board 6 and the like. The solar energy semicircular cavity dual-pipe heat collector has the advantages that after focused solar energy enters a semicircular cavity through the light inlet, the solar energy is reflected many times in the semicircular cavity and is repeatedly absorbed by the inner pipe, so that the heat absorption efficiency is improved. The solar energy semicircular cavity dual-pipe heat collector is simple in structure, and is convenient to manufacture, mount and use.