The wheel polygonal wear has been one of the most serious problems in China’s high-speed trains since they were put into operation in 2008, which directly affects the operation safety of high-speed trains. The abilities of improving the adhesive coefficient and repairing local defects by an abrasive block were experimentally studied on a high-speed wheel-rail rolling test rig. The frictional self-excited vibration model of a wheelset-track system consisting of a wheelset, two rails and monolithic track beds was established. The occurrence tendencies of friction self-excited vibration of the wheelset-track system under the wheel-rail adhesion and sliding conditions were studied. The main mechanism of suppression of the wheel polygonal wear by abrasive block was concluded as follows: (1) the ability of the abrasive block increasing the adhesive coefficient, which made it difficult for the wheel to slip on the rail upon braking or powering the train. Therefore, the conditions to initiate wheel polygonal wear no longer exisited; (2) the hard particles of the abrasive block can effectively remove the microscopic defects of the wheel tread in time, thereby can effectively suppress the polygonalization, abnormal wear and contact fatigue crack of wheels.