The invention provides a cover piece for preventing contents adhering. The outer surface of a thermal heating layer (5) stacked on a substrate layer (1) adopts wet silicon dioxide particles to form an anti-adhering layer (6). The wet silicon dioxide particles are formed by conducting hydrophobic treating on polyorganosiloxane having over 100cst of viscosity and especially dimethyl polysiloxane, which are used as treating agents. Or the outer surface of the thermal heating layer (5) stacked on the substrate layer (1) adopts the following wet silicon dioxide particles to form an anti-adhering layer (6). The wet silicon dioxide particles are hydrophobic wet silicon dioxide particles, whose di-n-butylamide adhering amount (DBA adhering amount) is below 200mmol/kg. The cover piece for preventing contents adhering is advantageous in that thermal sealing performance and sealing performance are well maintained; content like yoghourt can be effectively prevented from being adhered to the back face of the cover.