The invention provides a fruit fresh-keeping paperboard and a preparation method thereof. The fruit fresh-keeping paperboard consists of paperboard base paper and fresh-keeping coat which is spread on the surface of the paperboard base paper. The paperboard base paper is mainly made from the waste paper, and the base weight is 90 to 100 g/m2. The fresh-keeping coat mainly comprises the following components in part by weight: 1 part of cristobalite, 0.25 to 1.5 parts of kaolin, 0.005 to 0.01 part of sodium polyacrylate, 0.0003 to 0.0005 part of nisin, 0.0001 to 0.0003 part of natamycin, 0.2 to 0.5 part of oxidized starch and 1.0 to 2.0 parts of water, and the base weight is 5 to 30 g/m2. The waste paper is made into the paperboard base paper through, disintegration, high-consistency slag removal, defibering, low-consistency slag emoval and screening, the cristobalite, kaolin, the sodium polyacrylate, the nisin, the natamycin and water are added into a high-speed dispersion machine to be made into pigment dispersion liquid after being adequately dispersed and filtered, and the oxidized starch and the water are heated to be dissolved to obtain the oxidized starch liquid. The pigment dispersion liquid is mixed with the oxidized starch liquid to obtain the fresh-keeping paint liquid, after being filtered by 180 to 200-mesh sieve, the fresh-keeping paint liquid is spread onto the surface of the paperboard base paper through a spreading machine, and the paperboard base paper with the surface being coated with the fresh-keeping paint is secondarily dried, press finished and decorated to obtain the finished product. The fruit fresh-keeping paperboard has the advantages that the fresh-keeping effect is good, the environment compatibility is good, the fresh-keeping package and the storage and transportation package are integrated, and the continuous mass production can be realized on the papermaking machine.