The invention relates to the corrosion-resistant material fretting technology, in particular to a high-temperature high-pressure in-situ composite fretting test device, and solves the problems that composite fretting at high temperature and under high pressure is difficult to realize, fretting amplitude and frequency are difficult to measure and control accurately, radial load is difficult to accurately measure and adjust in real time, frictional force between friction pairs is difficult to measure, electrochemical signals are difficult to measure in the fretting process and the like. The device comprises a piezoelectric actuator, a tension and pressure sensor, a vibration exciter, a displacement sensor, linear guides, a high-pressure autoclave, a high-pressure autoclave cover, a working electrode/auxiliary electrode holder, a reference electrode holder, a hydraulic cylinder, a thermocouple, columns, a positioning plate, a first sample clamping device, a vertical movement shaft, a horizontal movement shaft, movement shaft guide brackets, an auxiliary electrode, a reference electrode, a working electrode, a guide platform plate, guide bars and the like. In-situ tangential fretting, radial fretting and bidirectional composite fretting are performed on surfaces of samples at high temperature and under high pressure.