Abstract: Objective: To improve the quality of abalone polysaccharide, the purification process by macroporous resins was optimized, and the immunomodulatory activities of polysaccharides before and after purification were evaluated. Methods: The purification effects of six kinds of macroporous resins on abalone polysaccharide were investigated with the comprehensive score of polysaccharide recovery rate, deproteinization rate and decolorization rate as the index. Single-factor experiment and response surface analysis were employed to optimize the purification process parameters. The immunomodulatory activities of abalone polysaccharide before and after purification were studied by cell experiment in vitro. Results: HPD100 had the best purification effect on abalone polysaccharide with the highest comprehensive score. The optimal purification process parameters were as follows: Polysaccharide to resin mass ratio 1:42, adsorption time 3.10 h, adsorption temperature 35 ℃. Under these conditions, the polysaccharide recovery rate, deproteinization rate and decolorization rate were 97.58%±1.58%, 30.20%±0.66% and 45.78%±1.01%, respectively, and the resulting average comprehensive score was 61.83%. Furthermore, the in vitro cell experiment results showed that the immunomodulatory activity of abalone polysaccharide was markedly enhanced after purification by HPD100, with stronger viability of RAW264.7 macrophages and higher secretion of cytokines including NO, TNF-α and IL-6. Conclusions: An optimal purification process of abalone polysaccharide by macroporous resins was obtained, and the purified polysaccharide exhibited significantly improved biological activity. This research would provide a theoretical basis for preparation of highly bioactive abalone polysaccharide.