The effects of bio-antagonists on the prevention of Valsa ceratosperma and the application in fruit postharvest fresh-keeping of apple and pear were analyzed in this paper. The fungus was classified into Galactomyces geotrichum by microexamination combined with molecular biology. The antagonistic effect of fungus on the fruit Valsa ceratosperma was studied based on the plate bacteriostasis and in vivo experiments, which indicated that the fungus could inhibit Valsa ceratosperma and 5×107 CFU/mL of the fungus had good effect on the prevention of pear and apple rot inoculated with 5×104 spores/ml pathogenic bacteria. Compared with the control fruit, the rot rate of pear treated by the fungi solution decreased 20% after storage 20 d and the apple decreased 30% after storage 60 d. Furthermore, the softening of fruit could be delayed and the fruit maintained good nutritional quality after treated by the fungus. The experiments showed that the fungus separated from sea had high potential in biological control of fruit disease and could be applied in the fruit preservative and fresh-keeping.