Bolt with screw rod adjustable in length

The invention discloses a bolt with a screw rod adjustable in length. The bolt is characterized in that the bolt comprises an assembling screw rod body and a screw rod body, the assembling screw rod body and the screw rod body are connected through internal threads and external threads of a connecting bolt body, and a bolt head end is arranged at the bottom end of the screw rod body. The connecting bolt body is divided into a connecting bolt body front section and a connecting bolt body rear section, the connecting bolt body front section and the connecting bolt body rear section are of an integrated structure, the connecting bolt body front section is provided with the external threads, and the connecting bolt body rear section is also provided with the external threads. The bolt has the advantages that by adding the connecting bolt body and through the matching of the internal threads and the external threads, adjustment and control over the length of the screw rod can be achieved, screw rods of multiple specifications are not needed, and therefore the production cost of the bolt is greatly lowered.