Valve actuator with adapter convenient to replace

The utility model discloses a valve actuator with an adapter convenient to replace, and belongs to the technical field of valve actuators. The gear box mainly comprises a box body and an output shaft, the output shaft is hollow to form a cavity, and the cavity comprises a first through hole, a second through hole and a third through hole close to the outermost end of the output shaft which are sequentially arranged in the axial direction of the output shaft. The adapter is used for being connected with the valve rod in a matched mode, the fastening piece is used for positioning the locking piece on the output shaft, the adapter is detachably inserted into the cavity and limited in the cavity in the circumferential direction, the locking piece is detachably contained in the third through hole, and the fastening piece is used for fixing the locking piece on the output shaft. The locking piece comprises a fastener used for axially positioning the adapter on the output shaft, and the fastener is detachably instal