The invention discloses a security anti-theft buckle, and belongs to the field of water tank wiredrawing machines. According to the main points of the technical scheme, the security anti-theft bucklecomprises a plug pin body and an inserting groove body matched with the plug pin body. The security anti-theft buckle solves the technical problem that a handle on an anti-theft lock is easily openedby a cardboard or other objects under the prior art, the effect that it is difficult for a person outside a door to open the door on the premise of without consent of the person inside the door is achieved, and the security anti-theft buckle is applied to theft prevention.