Microwave assisted extraction of polysaccharides from Panax notoginseng was optimized using single factor experiments and the orthogonal test. The mechanism underlying microwave assisted extraction was identified by laser diffraction particle sizing analysis, and the monosaccharide composition of polysaccharides was characterized by thin-layer chromatography. The optimal conditions for microwave assisted extraction were obtained:microwave duration of 8min, soaking time of 60min, ratio of liquid to solid of 30mL/g, and particle size of 200 meshes.The extraction yield of microwave assisted extraction (21.0mg/g) was significantly higher than that of conventional extraction (12.7mg/g). Thin-layer chromatography and solubility of polysaccharides were studied. Microwave assisted extraction was superior to conventional extraction in terms of the extraction yield. The possible reason was that microwave radiation facilitated the swelling of plant samples, and their structure became loose, which led to the exudation of polysaccharides. Polysaccharides from P. notoginseng were mainly composed of three monosaccharides, which were glucose, galactose and arabinose, while the pH value greatly affected solubility of polysaccharides from P. notoginseng.