A triaxial high temperature and high pressure rock mechanics load test platform includes a base, a lifting seat, and an intermediate connecting seat arranged between the base and the lifting seat. A hydraulic assembly is arranged between the base and the intermediate connecting seat; the intermediate connecting seat is connected with the lifting seat by means of a group of connecting rods; the lifting seat is enclosed by a side wall and a base plate to form a receiving groove with an upward opening; and a limiting device is arranged on the side wall of the lifting seat for preventing an MTS triaxial force sensor from disengaging from a support disk.