In this paper， response surface experiments according to the Box-Benhnken center combination principle was applied to optimize the extraction of polysaccharides from longan pulp by superfine grinding and enzymatic hydrolysis and the influencing factors as ultrasonic time， enzyme dosage and extraction time were evaluated； through the analysis of the basic composition， viscosity， polysaccharides solubility and molecular weight， physicochemical properties of longan polysaccharides（LP， LP-S， LP-SE） extracted by traditional hot water extraction， superfine grinding auxiliary extraction， superfine grinding and enzymatic hydrolysis auxiliary extraction were compared； the immune activity of longan polysaccharides （LP， LP-S， LP-SE） was compared by detecting the cytokines expression of macrophage. The results showed that ①The optimal technological parameters were conformed as follows： superfine grinding time 2 min， enzyme dosage 140 U/g， pH value 5， ratio of solid to liquid 1 ∶ 40， extraction temperature 50 ℃. Under these conditions， the experimental yield of polysaccharides was 38.49%； ②Compared to LP and LP-S， LP-SE had obvious differences including the higher yield， smaller molecular weight， lower viscosity and higher solubility， lower uronic acid， higher rhamnose and arabinose content； ③The ability of LP-SE to activate macrophages to secrete NO， IL-6， TNF-α， IL-1β， was significantly higher than that of LP and LP-S. The results indicated that the superfine grinding and enzymatic hydrolysis extraction can effectively change the physicochemical properties of polysaccharides and it showed the best immunoregulatory activity.