Pleurotus spp. was one of the most precious and common edible fungi, polysaccharides were the main active component. The structural, biological activities and structure-activity relationship (SAR) of polysaccharides from Pleurotus spp. were systematically reviewed. On the basis of structure and biological activity, structure-activity relationships were also analyzed and discussed to look forward to its future research direction and application prospect. In the past 5 years, about 30 kinds of polysaccharides were isolated from Pleurotus spp., and their preliminary structures were studied, but the fine structures were seldomly reported. The polysaccharides showed the activities of immunomodulatory, hypoglycemic, anti-inflammatory, antioxidant, anti-ageing, hepatoprotective, anti-tumor, hypolipidemic and regulating intestinal flora, but the mechanism was needed further study. There were few studies on the SAR of polysaccharides from Pleurotus, and the polysaccharides of P. eryngii were studied. It was found that the biological activities of polysaccharides were affected by molecular weight, monosaccharide composition, sugar chain structure and configuration. In addition, sulfonation and selenization could significantly increase the bioactivities of polysaccharides. These findings might help to better understand the research status of polysaccharides from Pleurotus spp. and provided a scientific basis for their application as functional foods.