The utility model provides a dust -proof membrane piece, includes the adhesive tape piece of disc, is equipped with a bellied rubber cylinder at the upper surface of adhesive tape piece, is equipped with first gasket on a rubber cylinder, is equipped with two bellied rubber cylinder at the lower surface of adhesive tape piece, is equipped with the second gasket on the 2nd rubber cylinder, is equipped with the connecting piece that passes first gasket, the 2nd rubber cylinder and second gasket on a rubber cylinder, it has the through -hole to distribute along the marginal circumference of adhesive tape piece. The through -hole can pass through bolt fixed connection with the installation mouth of pipe of equipment, because this dust -proof membrane piece includes the adhesive tape piece, the adhesive tape body is made through diping in the cloth to glue, has elasticity and toughness, can change the shape to the different production environmental requirements of adaptation. First gasket and second gasket make dust -proof membrane piece's overall structure firm.