Abstract: As porous medium，rocks are affected by ground water permeation. Elasto-plastic theory is used to analyze mechanical behaviors of the non-uniform stress field of circular tunnels and the circular tunnels elasto-plastic theoretical solution of non-uniform stress field is deduced. Base on the Mohr-Coulumb failure criterion, the boundary line equation of surrounding rock mass plastic zone under non-uniform stress field on the action of seepage is deduced. Through comparing whether the stability of surrounding rock was under the action of seepage or not, it obtains that the influence of seepage field on stress field is more intensive than without considering seepage when side pressure coefficient is 0.5. The study demonstrates that the influence of seepage field on stress field is intensive.