The Vigna umbellata lectin as the research object, based on the results of single factor experiments, the extraction process is optimized by response surface experiments. Further purification was made by using ammonium sulfate fractionation precipitation method,Q Sepharose XL anion exchange chromatography, phenyl FF HP hydrophobic chromatography and Sephadex G-50 gel filtration chromatography, and the protein was analyzed by SDS-PAGE electrophoresis. The results showed that the optimum extraction parameters were as follows: PBS is used as the extracting solution, the ratio of material to liquid was 1∶23 (g/mL), pH value was 7.8, and the duration was 14 h and the agglutination activity of lectin was (37.18±0.18) HU. The agglutination activity of the purified lectin reached 127 HU. Identification of purified lectin has two subunits and the molecular weights were around 55 kDa and 27 kDa.