Abstract: Lectin from Laetiporus sulphureus was a kind of protein,which could be extracted from Laetiporus sulphureus fruiting bodies and could agglutinate red blood cell. In the paper,the Laetiporus sulphureus was used as a raw material with extraction phosphate buffer. On the basis of single factor experiments,such as sodium chloride concentration,liquid- solid ratio,extraction temperature,extraction time,extraction p H value,four factors and three levels orthogonal experiment was designed to study lectins optimum extraction of the Laetiporus sulphureus. The results showed that the optimum conditions of extraction technology were sodium chloride concentrations of 0 mol / L,liquid- solid ratio of 30 ∶ 1 m L / g,extraction temperature of 15 ℃,the extraction time of10 h,the extraction p H of 7.5.Under the conditions of the extraction,agglutination activity of Laetiporus sulphureus lectin reached 0.5870 and the extraction rate of protein reached 0.576%.