Abstract: In order to select the optimal process conditions for extracting Se-polysaccharide from Magnolia officinalis,we conduct the experiment on the Magnolia officinalis growing in the high - selenium area of Enshi. We get the polysaccharide through water extraction and alcohol precipitation using orthogonal experimental design, determine the polysaccharide content by sulfuric acid-phenol method, detect the selenium content by atomic fluorescence spectrometry,and set the amount of polysaccharide as the index to explore the influence of the following conditions: raw material -liquid ratio, microwave processing time and extraction time. The result shows that the optimal conditions for polysaccharide extraction are as follow: raw material -liquid ratio set to 1：100, 4 min microwave treatment, 90 min extraction. The extraction rate should be 2.022% and Selenium content of polysaccharides can be 0.1305 μg/g under the extraction conditions described above.