Abstract: The study on the effect of loquat polysaccharides on the immunity of Carassius auratus could provide some evidences for controlling the disease of aquatic animal and making full use of resources of loquat. Therefore, taking the Carassius auratus as testing material, the Carassius auratus was immune by being injected with loquat polysaccharides, in order to study the effect of loquat polysaccharides on superoxide dismutase, lysozyme, phenoloxidase and phagocytic rate. The results showed that:when the Carassius auratus was injected with 1.0 mg·mL^-1 loquat polysaccharide for 21 hours, the blood SOD and lysozyme reached the highest, which were respectively 37.8 U and 128 U; when the Carassius auratus was injected with 5 mg·mL^-1 loquat polysaccharide for 28 hours, the blood phenoloxidase activity and phagocytic rates reached the peak value, which were respectively 4.1 U and 55.68%, showing that the loquat polysaccharides could enhance the immune function of Carassius auratus.