The invention discloses a system for accurately testing friction damping. The system comprises a piston, a damping sealing member, a sleeve, a piston rod, force sensors, a cutting sleeve coupler, a displacement sensor, a driving motor, a measurement control platform, an experiment table body and a sleeve centering adjusting rod. The piston, the damping sealing member and the sleeve are matched together to simulate a moving part structure of a liquid rocket valve, and then are assembled together with the experiment tale body and the sleeve centering adjusting rod to form an experiment table offriction testing system; the piston is in rigid connection with the driving motor through the piston rod and the cutting sleeve coupler; the force sensors at two ends of the sleeve and the displacement sensor of the driving motor are connected with the measurement control platform; and the driving motor is connected with the measurement control platform to form a control test bed of the friction testing system. The system provides a valve piston friction structure for simulating reality, adopts a driving mode combining direct driving and macro-micro motions, and has the advantages of automatic control, high control accuracy, high reciprocating frequency, large motion stroke, high dynamic frictional force measurement accuracy and the like.