The utility model provides an occluding device for the central passage of shutoff preventer, it includes: has the body that first end and second were held, the outer diameter of body and the radial dimension looks adaptation of central passage, set up a sealing mechanism and the 2nd sealing mechanism at first end and second end respectively, when the body holding was in the central passage, a sealing mechanism and the 2nd sealing mechanism top were solid on the preventer. The utility model provides an occluding device can be when meetting the oil gas well and take place the condition of low pressure overflow, better the central passage of shutoff preventer to reach and prevent the mesh that spouts.