The invention discloses an anti-theft bolt capable of secondary tightening, which comprises a bolt main body, an anti-theft block, a rotating rod, a limit ring, a fixed block, a limit bolt, and an auxiliary hole. The bolt main body is composed of a bolt head and a main screw rod. The main screw rod is fixed on the lower end of the bolt head, and the lower end of the anti-theft block is provided with a cylindrical accommodation groove, the anti-theft block is covered on the bolt head, and the bolt head extends into the accommodation groove, and a A rotatable rotating rod, a limit ring is fixed at the bottom of the rotating rod, a fixed block is arranged on the upper end of the bolt head, and a limit groove is arranged on the fixed block, the limit ring is inserted into the limit groove, and the A limit bolt arranged laterally is screwed on the fixed block. The invention cooperates the rotating rod, the fixed block and the limit bolt so that the anti-theft block can effectively cover the bolt head, and the anti-theft block can rotate under the condition that the bolt head does not move, so that the bolt has better anti-theft performance.