The invention relates to a testing machine used for studying the mechanical power consumption of an internal combustion engine, in particular to an internal combustion engine cylinder sleeve-piston ring friction performance testing machine with the variable reciprocating stroke. The internal combustion engine cylinder sleeve-piston ring friction performance testing machine with the variable reciprocating stroke comprises a platform (24) and a bottom plate (31) and is characterized by further comprising a belt wheel axle (6), a support (7), a large belt wheel (9), a variable-radius crank disc (10), pin holes (11) for installing cylindrical pins, a connecting rod (12), an adjusting rod guide base (13), an adjusting rod (14), a guide rail (15), a loading hole (16), a cantilever beam (17), a piston ring clamp (18), a piston ring test piece (19), a cylinder sleeve test piece (20), a tension and pressure sensor (21), a cylinder sleeve base (22), a sensor support (23), a measuring rod (32) and the like. According to the internal combustion engine cylinder sleeve-piston ring friction performance testing machine with the variable reciprocating stroke, parameters are easy to control, the test pieces are easy to obtain, test data is high in precision, and contact conditions are easy to simulate.