The invention belongs to the field of papermaking technology, and particularly relates to a plastic-free environment-friendly isolation paper and a plastic-free environment-friendly release paper used for the industry fields of food hygiene, pharmaceutical packaging, electronic appliances, household products, cosmetics, supermarket logistics, post express and the like and a preparation method of the plastic-free environment-friendly isolation paper and the plastic-free environment-friendly release paper. The technical scheme is as follows: the isolation paper is composed of a 30-60g/m<2> low-weight tissue paper or a 50-200g/m<2> cultural paper, and a precoating layer and an isolation layer coated in sequence on the tissue or cultural paper surface, wherein a layer of precoating is coated on the front face of the base paper firstly and then a layer of isolation layer is coated into the precoating layer; the release paper is formed by coating a solvent-free silicone oil onto the isolation paper and comprises the base paper layer, the precoating layer, the isolation layer and the silicone oil layer from top to bottom in sequence. The paper prepared by the method provided by the invention has the characteristics of low requirements for base paper performance, good isolation (release) effect, high paper smoothness, no pollution, easiness of recycling, stable properties and the like. The production process has the advantages of low manufacture cost, high production efficiency, easiness of mass production and the like.