The invention relates to a water soluble preservative film for fruits and vegetables and a preparation method of the preservative film. The water soluble preservative film for the fruits and vegetables is mainly prepared by the following materials in percentage in weight: 50 to 80% of polyvinyl alcohol with alcoholysis degree of less than 90%; 10 to 30% of polyhydroxy plasticizer, 1 to 5% of auxiliary film forming agent, 3 to 8% of low temperature antifreeze agent, 3 to 10% of adsorbent filling agent and 0.3 to 2% of film-forming adding additive. The preparation method comprises the following two steps of: 1, after metering contents of components of the preservative film in the formula, obtaining a uniform aqueous solution with concentration of 15 to 25% in water; and 2, uniformly casting the prepared solution on a clear steel band, and drying the solution to obtain the film through a dried drying tunnel with temperature of 120 to 180 DEG C. The preservative film has a high barrier property against oxygen, carbon dioxide and nitrogen and the like, and has a high bidirectional permeable exchange capacity for steam, thereby guaranteeing free breathing and water exchange of the fruits and vegetables in a preserving process.