An improved structure bolt snap wherein a check member is situated in the movable bolt of the bolt snap retaining body to provide for the open and closed states of the retaining body via the actuating member horizontal smooth section located in the movable bolt passage, the external threads at the outermost extremity of which are fastened to the check member inside the movable bolt. When the retaining body is closed, the actuating member is rotated until the check member fastened to the actuating member is exposed at the outer periphery of the retaining body bore, disabling the downward movement of the actuating member such that the retaining body is maintained in a closed state, thereby effectively ensuring safe closure and coupling.