The utility model relates to a straight insertion self-locking electric connector which mainly includes a changeover socket and a socket. The changeover socket includes a changeover socket housing, an insulator, a contact, an O-shaped ring, and a shaft sleeve assembly, wherein the insulator is connected with the contact; the insulator is arranged in the changeover socket housing; the insulator is connected with the changeover socket housing via the O-shaped ring; and the shaft sleeve assembly is arranged at a central axis position of the changeover socket housing. The socket mainly includes a socket housing, a pin insulator assembly, a socket O-shaped ring, and a socket insulator, wherein the pin insulator assembly is connected with the socket insulator and is arranged in the socket housing; and the pin insulator assembly is connected with the socket housing via the socket O-shaped ring. The straight insertion self-locking electric connector can overcome the defects of a conventional electric connector. The straight insertion self-locking electric connector is simple in structure, and is easy to operate, connect, and separate, and has high product operability and excellent tightness, thus having big economic value and social value.