The invention provides a testing device for acquiring a variable-strength steel plate differential temperature formation limit. The testing device comprises a punch, and further comprises an upper support plate, a lower support plate, a sliding block, a guide column, a support column, a base, a main cylinder, a side pressing cylinder, a light source, a high-frequency camera and a thermal infraredimager, wherein the punch comprises a punch main body, an embedded lump and a ceramic thermal insulating layer; the ceramic insulating layer is arranged in the middle of the punch main body and is fixedly connected with the punch main body; the embedded lump is fixed at the bottom of the punch and forms a spherical surface in smooth transition together with the punch main body; deep holes in whicha heating rod and a thermocouple are mounted are formed inside the punch; a threaded hole for connecting a connecting rod is formed in the top of the punch; a high-frequency sensing heating coil andan infrared probe which form a closed loop control system are respectively arranged around a convex mold side pressing ring and a concave mold side pressing ring. By controlling temperatures on two sides of the punch, a high-temperature testing sample part has different quenching velocities on two sides of the punch, then the differential temperature formation process of a variable-strength steelplate can be simulated, and the differential temperature formation limit of the variable-strength steel plate is acquired through a strain field acquired by using the high-frequency camera.