The utility model discloses a hydraulic motor of low noise, including the casing, rotate to set up the transmission shaft in this casing and set up at the epaxial eccentric sleeve of this transmission be provided with an odd number connecting rod - plunger subassembly in the casing on this eccentric sleeve's radial circumferencial direction, the outer wall parcel of every plunger has the cylinder liner in the casing, is equipped with plunger bushing, its characterized in that at the global tip of casing radially: contact surface between the tip of plunger bushing and the tip of casing is the reference surface, being formed with the clearance between the tip of plunger bushing and the tip of cylinder liner, opening to have on the tip of this cylinder liner and fall the groove of making an uproar, fall the inslot of making an uproar at this and be equipped with sealing washer and non metallic member retaining ring in proper order, this non metallic member retaining ring offsets with the tip of plunger bushing. The utility model discloses utilize nonmetal retaining ring to keep apart cylinder liner and plunger bushing, can effectively solve the current big problem of hydraulic motor operating noise, improve hydraulic motor's life.