The disclosure provides a pipeline deformation detection PIG, including: a detection body and a foam body; the detection body is arranged in the foam body, and the detection body includes: a pressure sensing element; and the pressure sensing element includes: a pressure sensor and a pressure coupling unit. The detection body of the pipeline deformation detection PIG of the present disclosure is provided in the foam body, the inner side surface of the pressure coupling unit is in contact with the force receiving surface of the pressure sensor, and the outer side surface is in contact with the inner wall of the pipeline to be detected, the pressure coupling unit can translate the pipeline deforms into pressure according to coupling deformation, and meanwhile solve the stuck problem of the existing detection PIG in a large deformation pipeline.