Periplaneta americana is favored by researchers because its wide range of pharmacological activities,but its polysaccharide hydrolytic process and antioxidant activity are rarely reported.The hydrolytic conditions of P. americana polysaccharide were optimized by response surface method.The influence of hydrolysis time,hydrolysis temperature and the dosage of trifluoroacetic acid on the hydrolysis of P. americana polysaccharide were determined by single factor experiment.The total peak area of monosaccharides in the high performance liquid chromatography (HPLC) was used as the response value,and the optimal hydrolysis conditions for P. americana polysaccharide were determined,which were combined with response surface method.The optimum hydrolysis conditions of the polysaccharide of P. americana were as follows:the hydrolysis time was 1 h，the temperature was 120 ℃，the amount of trifluoroacetic acid was 3.5 mL，and the total peak area of monosaccharides were measured by HPLC,under which the total peak area of monosaccharides was the largest.At the same time,The reducing ability and scavenging ability of P. americana polysaccharide on DPPH,OH and ABTS free radicals were determined by antioxidant activities test in vitro.P. americana polysaccharide have a good scavenging capacity for DPPH,OH and ABTS free radicals,with IC₅₀ of 0.028,0.78 and 0.07 mg/mL,respectively,which has a certain reducing capacity.In this study,a method for the analysis of monosaccharides composition in the polysaccharide of P. americana was established,and its hydrolytic process and antioxidant activities were studied,which provide scientific basis for the development and utilization of resources of P. americana.