The invention discloses a locking pin, and relates to the technical field of mechanical connecting components. The locking pin comprises a pin body, wherein the pin body is a straight rod, a groove is formed in the side of the pin body, a cover plate used for sealing the notch of the groove is mounted on the pin body, a movable tenon and an elastomer are clamped and arranged in a cavity which is formed by surrounding the cover plate and the groove, the movable tenon is provided with a tenon head which extends out of the pin body from the groove wall of the groove and limiting parts which are placed in the groove, one ends which are connected with the tenon head of the limiting parts are butted against to the groove wall of the groove, the free ends of the limiting parts are in butted connection to the elastomer, and the limiting parts and the elastomer are sealed in the cavity. Compared with the prior art, the locking pin disclosed by the invention has the advantages that the locking pin is more suitable for the severe environment, the service life is long, the structure is simple, the processing and the assembling are easy, the component replacement is convenient, and the usage cost is low.