The utility model discloses a compensating gear which is used as a power coupling device for a hybrid car, aiming at overcoming the problem that the planetary gear(3) and the planetary gear shaft(4) of the compensating gear in the prior art have serious sliding abrasion after running for a long time, which results in incorrect meshing of the planetary gear(3) and the axle shaft gears. The compensating gear comprises a compensating gear shell(1), a left axle shaft gear(2), a planetary gear(3), a planetary gear shaft(4), roller pins (5) and a right axle shaft gear(6). The additionally arranged roller pins(5)are evenly installed between the axle hole of the planetary gear(3)and the shaft tip of the planetary gear shaft(4) of the compensating gear; the symmetry axis of the roller pins(5) and the symmetry axis of the planetary gear shaft(4)are parallel to the symmetry axis of the axle hole of the planetary gear(3); and the cylindrical faces of the roller pins(5) and the cylindrical face at the shaft tip of the planetary gear shaft(4) at the inner sides of the roller pins are in rolling connection with and at the same time in contact with the cylindrical face of the axle hole of the planetary gear(3) at the outer sides of the roller pins of the compensation gear.