The utility model discloses a hydraulic remote control locking device for the expansion joint of ocean standpipes. The upper flange of the expansion joint is connected fixedly with the inner cylinder of the expansion joint through a locking sleeve; an upper connection cylinder body is sleeved on the outer circumference of the inner cylinder and connected with the outer cylinder of the expansion joint, meanwhile the inner is inserted into the outer cylinder. The hydraulic remote control locking device comprises a plurality of hydraulic locking units arranged along the circumference of the upper connection cylinder body, each hydraulic locking unit is connected with the a remote hydraulic control device through a hydraulic pipeline; each hydraulic locking unit comprises a hydraulic locking cylinder, a lock pin and a spring are arranged in the piston chamber of the hydraulic locking cylinder, one end of the piston chamber is connected with the hydraulic pipeline or a lock pin is arranged in the piton chamber of the hydraulic locking cylinder and both ends of the piston chamber are respectively connected with the remote hydraulic control device through a hydraulic unlocking pipeline and a hydraulic locking pipeline. The utility model can realize automatic locking and unlocking of the expansion joint of the ocean underwater standpipes conveniently and reliably.