Objective　To examine the soluble protein patterns of three ordinary species of cockroaches in Anhui province by SDS-PAGE technique, and to find the method of scientific classification for cockroaches. Methods　The soluble protein liquid was made by the way of freezing and melting homogenate. SDS-PAGE was carried out in the liquid. After using Coomassie brilliant blue G250, the molecular weight of all of protein strips were measured and calculated by standard curve. Results　The numbers of female and male of Periplaneta fuliginosa were 31 strips and 29 strips; the numbers of female and male of Periplaneta Americana were 30 strips and 28strips; the numbers of female and male of Blattella germarica were 28 strips and 25 strips. The number and location of protein bands were different among these species. It was also obvious that the positions of the main protein bands in Blattella germarica were different from those in two Periplaneta species, and the positions of the main protein bands in female insect were different from those in male insect. Conclusion SDS-PAGE can be used as one of classification methods for cockroaches.