In order to improve the extraction yield of polysaccharide from tamarind seeds (TSP) and decrease its protein mass fraction, the extraction conditions of raw material mesh, extraction pH, and extraction temperature were optimized by using the response surface methodology and taking the polysaccharide yield and protein mass fraction as two obtimization objectives. The resultant optimal conditions for giving the highest polysaccharide yield and the lowest protein mass fraction were as follows: the raw material mesh 118, extraction pH 3.06 and extraction temperature 90 ℃. Under these conditions, the theoretical maximal yield of TSP is 49.76%, and the minimal protein content is 1.00%. The practical conditions based on the simulated optimal conditions were somewhat modified to the raw material mesh 120, extraction pH 3.1 and extraction temperature 90 ℃. The actual value of polysaccharide yield was 49.59%±0.36%, and that of protein mass fraction was 1.02%±0.05%, which were highly consistent with the predicted value by the model. The results indicate that the optimization of extraction conditions is of practical significance and will provide a foundation for the pilot scale production of TSP.