Abstract: Disclosed is a heavy-release force release film having surface microviscosity and a preparation method thereof A release layer of the release film comprises: by mass, 10 to 25 parts of vinyl silicone oil, 0.5 to 5 parts of a cross-linking agent, 15 to 40 parts of silicon resin, 25 to 60 parts of a pressure-sensitive adhesive, 1 to 6 parts of a curing agent, and 30 to 60 parts of a diluent. The preparation method comprises: removing water, static electricity, dust and foreign matters on a surface of a substrate; uniformly stirring vinyl silicone oil, the cross-linking agent, the pressure-sensitive adhesive, silicon resin and the diluent according to the above mass part ratio; adding the curing agent into the mixture and stirring; coating the release agent on a processed surface of the substrate, drying and carrying out rolling-up.