The utility model discloses an expansion bolt comprises bolt, nut, plain washer and the section of thick bamboo that expands, the left end portion of bolt is equipped with the external screw thread to it has interior hexagonal to sink the groove to open, the right -hand member of bolt is equipped with takes tapered tail cone, the left end of a section of thick bamboo of expanding be equipped with with bolt complex internal thread, the right -hand member is equipped with two at least groove of the notchs, a section of thick bamboo, plain washer and the nut of expanding is adorned in proper order in the bolt, by internal thread and the heavy groove control bolt of interior hexagonal and the section of thick bamboo axial motion relatively that expands. The utility model provides an expansion bolt, not only the location is accurate, has solved the problem that a bloated section of thick bamboo and bolt can't take out moreover, does benefit to construction position's restoration and secondary construction.