The polysaccharide obtained from the branches and leaves of Chrysanthemum indicum was extracted by microwave assisted extraction after its powders decolorized and degreased, and then the polysaccharide extraction content was determined by phenol-sulfuric acid method. The extraction process of the polysaccharide was studied by single factor experiment which controlled liquid-solid ratio, extraction temperature, extraction time, and microwave power, and the orthogonal experiment was tested and based on single factor experiment, then determined the best extraction process. Those free radical cleared effects of its polysaccharide were tested by Fenton reaction and DPPH reaction. The results showed that the polysaccharide extraction content from the branches and leaves of C. indicum could reach 6.32% when solid-liquid ratio was 140 (g/mL), extracted by using microwave power (450 W) at 80 ℃ for 10 min. The anti-oxidant activity tests of the polysaccharide from the branches and leaves of C. indicum showed a good scavenging activity on ·OH and DPPH·, and the relationship between the polysaccharide and hydroxyl free radical clearance was found to be an concentration reliable. Finally, the polysaccharide was verified to be an untapped antioxidant substance.