Abstract: In order to increase the application value of rape polysaccharide, the optimization of rape polysaccharide extraction process was studied with cruciferous plants of the Brassica chinensis as the research object. The rape was dried, crushed, through 100 mesh sieve and degreased. Rape polysaccharide was extracted by hot water extraction according to the extraction time, extraction temperature, extraction water ratio and times of extraction on condition of single factor experiment. The extraction optimization conditions of rape polysaccharide were obtained by orthogonal experimental design. The yield of rape polysaccharide was 17.85% under the optimum condition for the single factor; the yield of rape polysaccharide was 19.18% under the orthogonal optimization optimal conditions. The optimum extraction conditions of rape polysaccharide showed that the water content was 40 (1 g: 40 mL), the extracting temperature was 100℃, the extracting time was 1.5 h, the number of extraction times was two.