Connecting plug

The utility model discloses a connecting plug comprising a connecting plug body which is provided with four holes extending from a front end surface to direction of a rear end surface. The centers of circles of the four holes are connected so that a square is formed. Each hole is composed of a first hole and a second hole. The first hole is close to the front end surface. Diameter of the first hole is greater than diameter of the second hole. A conical step is arranged on the contacting part of the first hole and the front end surface. The front end surface is provided with an insulting layer which is provided with four holes II which are corresponding to the holes. The front end surface of the connecting plug is provided with the insulating layer so that wearing resistance between the connecting plug and connecting members can be effectively enhanced, and possibility of electric leakage can also be prevented. The connecting plug body is provided with an antiskid mat and antiskid stripes so that connection of the connecting plug is facilitated.