Biological preservative for oranges

The invention discloses a biological preservative for oranges, consisting of cryptococcus laurentii suspension, rhodotorula glutinis suspension, rhodosporidium suspension, salicylic acid, auxin, calcium chloride and water, wherein each liter of preservative contains 1*1010-1*1012 cryptococcus laurentii cells, 1*1010-1*1-12 rhodotorula glutinis cells, 1*1010-1*1012 rhodosporidium cells, 1-100mg ofsalicylic acid, 10-20mg of auxin, 5-50g of calcium chloride and the balance of water; the preservation number of the cryptococcus laurentii is CGMCC (China General Microbiological Culture Collection)NO.3590, the preservation number of the rhodosporidium is IMI (Innovative Medicines Initiative) 394084 and the preservation number of the rhodotorula glutinis is CGMCC NO.3589. The biological preservative for oranges, which is disclosed by the invention, can be used for effectively controlling postharvest diseases of orange fruits on the premise of no use of chemical bactericide.