Abstract: To explore the ultrasonic microwave assisted extraction technology and the functional activity of polysaccharides from Umbilicaria esculenta.The ultrasonic microwave synergistic extraction method was used, and the effects of microwave power, extraction time and the ratio of material to liquid have been investigated on the extraction rate of polysaccharides from U.esculenta.On the basis of single factor experiment, the extraction technology of polysaccharides from U.esculenta was optimized by L₉ ( 3³) orthogonal experiment.The results showed that the optimum extraction process of polysaccharides from U.esculenta as follows: the micro-wave power was 150 W, the ratio of material to liquid was 1 ∶ 30 ( g∶ m L) , and the ultrasonic micro-wave synergistic extraction time was 240 s.The extracted polysaccharides were 12.87%.In vitro antioxidant activity of polysaccharides from U.esculenta was studied by the scavenging activities of DPPH free radical.The results showed that the polysaccharides had higher antioxidant activity in vitro, and the scavenging rate of DPPH free radical was 65.62% at the concentration of65 μg/m L. MTT method was used to analyze the inhibitory effect of polysaccharides from U.esculenta on proliferation of Hep G2 cells in vitro. The results showed that the inhibitory effect of polysaccharides on Hep G2 cells was obvious. In the range of0.001² mg/m L, the inhibition rate of Hep G2 cells showed a sharp rise. As the concentration of polysaccharides was10 mg/m L, the inhibition rate was 87.79%.And the IC₅₀ value was 0.6637 mg/m L.