The extraction conditions of maca polysaccharides were optimized and its antioxidant activity and hypolipidemic effect in vitro were explored. Response surface methodology of ultrasonic-assisted hot water leaching method was used to optimize the extraction conditions of maca polysaccharides. Free radical scavenging rate and cholate binding capacity were used to evaluate the antioxidant activity and the hypolipidemic effect of maca polysaccharides, respectively. Under the conditions of extraction temperature at 50℃, extraction time of 42min, ultrasonic power at 220W and material-liquid ratio at (g/mL) 1∶32, the extraction rate of polysaccharide reached a maximum of 11.0%.Furthermore, maca crude polysaccharides (MCP)were separated by an ion exchange column to obtain three components, named maca polysaccharides 1(MPS1),maca polysaccharides 2(MPS2) and maca polysaccharides 3(MPS3). Among them, MCP, MPS1 and MPS2 had strong antioxidant activity. The best scavenging rate of DPPH radicals by MCP,MPS1 and MPS2 reached 83.9%,81.8% and 63.7%, and the best scavenging rate of hydroxyl radicals reached 73.3%,56.8% and 76.7%, respectively. In addition, the binding rate of MPS3 to sodium taurocholate and sodium glycocholate in vitro was 49.1% and 32.2%, respectively. The results suggested that MCP, MPS1 and MPS2 had good antioxidant activity, and MPS3 owned certain hypolipidemic effect.