We study the susceptible-infected-susceptible (SIS) epidemic model on bipartite graph. According to the dif-ference of sex conception in weste and oriental nations, we construct the Barabasi Albert-Barabasi Albert (BA-BA) model and Barabasi-Albert Homogeneity (BA-HO) model for sexually transmitted diseases (STDs). Applying the rate equation approach, the positive equilibria of both models are given analytically. We lind that the ratio between infected females and infected males is distinctly different in both models and the infected den-sity in the BA-HO model is much less than that in the BA-BA model. These results explain that the countries with small ratio have less infected density than those with large ratio. Our numerical simulations verify these theoretical results.