Abstract: Through engineering example and using the software integration system of VB6.0 and FLAC3D,shield tunnel excavation face stability is analyzed with and without the consideration of seepage effect of water.According to the stability theory,the limit face pressure is that when face pressure is changed very small,displacement of the center at tunnel face increases large suddenly.And the changes of the support pressure,the stress field,the displacement field and the plastic zone are obtained under two kinds of conditions.The results show that the limit support pressure of face is equal to the total of the effective pressure and seepage force,the support pressure is larger with the consideration of seepage effect than without the consideration of seepage effect,the seepage force is the main of the limit support pressure;because of the pore water pressure,the stress of the tunnel face when considering the seepage effect is lower than without the consideration of seepage effect,the displacement and the plastic zones when considering the seepage effect is much bigger than that without the consideration of the seepage effect;and the stability of the face when considering the seepage effect is worse than without the consideration of the seepage effect.Comparison between the simulated results and the observed ones shows the software system is rational and valid and can provide useful reference to the setting of tunnel face support pressure in design and construction.