The invention provides a self-cleaning venting plug for a core casting mold. The self-cleaning venting plug comprises an elastic filter screen and a cylinder. The two ends of the cylinder are an open end and a filter screen end. The elastic filter screen is mounted at the filter screen end of the cylinder. The elastic filter screen is provided with a plurality of vent holes. The ratio of the thickness to the diameter of the elastic filter screen is 0.01-0.05. The venting plug can slightly deform under the typical sand shooting pressure to store stress. After the sand shooting pressure is eliminated, the venting plug releases the stress and recovers the shape. In the shape recovering process, sand grains and resin particles on the surface of the elastic filter screen are shaken off; accordingly, the sand grains and resin in the vent holes are removed, and the self-cleaning effect is achieved. The venting plug can clean the sand grains and the resin blocked in a venting system by itself. The cleaning frequency of the venting plug is reduced, and the service life of the venting plug is prolonged.