The invention relates to a relieving device of a railway vehicle basic braking parking cylinder. The relieving device is fixed to the side face of an end cover of the parking cylinder and comprises a box body, a center shaft, a bolt and a driver. The center shaft is located in the box body and can slide in the direction of the axis of itself. The rear end of the bolt and the center shaft are fixed, the center shaft is sleeved with the driver, and the front end of the bolt is provided with a head portion and a hook portion, wherein the head portion can be inserted between teeth of a ratchet wheel seat and the hook portion is matched with a locking pin. The two sides of the driver are connected with draw cords respectively, and the draw cords are parallel with the center shaft. A first stopping block used for preventing the head portion of the bolt from deviating and a second stopping block used for preventing the bolt from overturning are fixed to the end cover. Handles of the two draw cords are arranged on the two sides of a vehicle body respectively, and relief of parking brake can be realized by simply pulling the manual relieving draw cord on any side of the vehicle body.