This study explored the effects of adding shiitake polysaccharides (SP) on the physicochemical properties and antioxidant capacity of pork meatballs at different refrigeration stages (0, 2, 4, 6, and 8 days). Pork meatballs added with different amounts (m/m), namely 0% (control), 0.5%, 1.0%, 1.5%, and 2.0% of SP were prepared and evaluated for changes in moisture content, texture characteristics, degrees of lipid and protein oxidation during refrigeration. The results showed that addition of SP increased the moisture content and sensory score, and significantly decreased the hardness of pork meatballs compared with the control group (P < 0.05). With increasing addition SP, the elasticity and chewiness first increase and then decrease. SP addition increased the antioxidant potential and significantly decreased the carbonyl and sulfhydryl contents, thiobarbituric acid reactive substance (TBARS) value, and peroxide value (POV) during the refrigeration period (P < 0.05). At the late stage of refrigeration, there was no significant difference between pork meatballs added with 1.5% and 2.0% SP. In addition, correlation existed among the tested quality indicators of pork meatballs. To sum up, adding 1.5% SP was the most effective in inhibiting the oxidation of lipids and proteins and improving the quality of pork meatballs.