The utility model discloses a washable one-way throttle valve which comprises a valve body, a valve core arranged in a valve body inner bore and a spring arranged in a valve core counter bore. The valve core is movably connected with the valve body inner bore. One end of the valve core is provided with a through hole which intersects with the valve core counter bore in a vertical mode. An outer cone surface of one end of the valve core is provided with a throttling groove which is through in the axial direction. One end of the spring abuts against the valve core step counter bore. The other end of the spring abuts against a locking ring at one end of the valve body inner bore. When the valve core is closed, the outer cone surface of one end of the valve core is pressed on the inner cone surface of the valve body inner bore. Due to the fact that one side of the outer cone surface of one end of the valve core is provided with the throttling groove which is through in the axial direction, the washable one-way throttle valve has the advantages of being simple in structure and not easy in clamping stagnation of foreign matter. Hydraulic oil is capable of washing the throttling groove effectively. The foreign matter in the throttling groove is washed away so that blocking is avoided, and therefore normal operation of the entire system is guaranteed, and operational safety of an excavator is improved greatly.