[Objective]This study aimed to investigate the optimal extraction process of crude polysaccharides from wild Lactarius volemus Fr. in Yunnan Province and preliminarily analyzed its antioxidant activity in vitro. [Method] With water extraction and alcohol precipitation method,the optimal conditions for extracting crude polysaccharides from wild L. volemus Fr. were screened by single-factor and orthogonal experiments. The antioxidant activity of the extracted crude polysaccharides was determined with DPPH assay. [Result] The optimal conditions for pigment removal with activated carbon were: activated carbon amount of 20 g / L,water bath time of 40 min,water bath temperature of 40 ℃; the optimal conditions for extracting crude polysaccharides from wild L. volemus Fr. with hot water extraction method were: hot water extraction time of 3 h,solid-liquid ratio of 1∶ 45,extraction frequency of twice. Under the optimized extraction conditions,the yield of crude polysaccharides was 21. 33 mg / g. In addition,the antioxidant activity of 0. 665 mg / ml crude polysaccharides was 52. 46%; the amount of crude polysaccharides was proportional to the antioxidant activity. [Conclusion]Hot water extraction method can be used as a high-efficiency extraction technology of crude polysaccharides from wild L. volemus Fr. with simple operation and low costs. Crude polysaccharides extracted from L. volemus Fr. exhibited certain antioxidant activity in vitro. [Objective] This study aimed to investigate the optimal extraction process of crude polysaccharides from wild Lactarius volemus Fr. in Yunnan Province and preliminarily analyzed of antioxidant activity in vitro. [Method] With water extraction and alcohol precipitation method, the optimal conditions of extracting to crude polysaccharides from wild L. volemus Fr. were screened by single-factor and orthogonal experiments. The antioxidant activity of extracted crude polysaccharides was determined with DPPH assay. [Result] The optimal conditions for pigment removal with activated carbon were: activated carbon amount of 20 g / L, water bath time of 40 min, water bath temperature of 40 ° C; the optimal conditions for extracting crude polysaccharides from wild L. volemus Fr. with hot water extraction method were: hot water extraction time of 3 h, solid- liquid ratio of 1:45, extraction frequency of twice. Under the optimized extraction conditions, the yield of crude polysaccharides was 21. 33 mg / g. In addition, the antioxidant activity of 0. 665 mg / ml crude polysaccharides was 52. 46%; the amount of crude polysaccharides was proportional to the antioxidant activity. [Conclusion] Hot water extraction method can be used as a high- efficiency extraction technology of crude polysaccharides from wild L. volemus Fr. with simple operation and low costs. Crude polysaccharides extracted from L. volemus Fr. samples certain antioxidant activity in vitro.