Abstract: Objective: The tunnel section from Xiangjiang Road Station to Jinggangshan Road Station on Qingdao Metro Line 13 crosses under the ancient canal, in order to ensure the construction safety of the typical water\|rich loose strata, it is necessary to study the impact of subway tunnel construction on the ancient canal. Method: The project overview of the subway section is described, and the influence of initial moisture content, particle size and saturation three parameters on seepage coefficient is analyzed. A laboratory test is carried out to study the characteristics of unsaturated seepage in water\|rich loose formation. The saturated percolation\|stress coupling calculation module built in FLAC3D software is modified, and an improved one is obtained considering the strength changes of surrounding rock after damage. The measured and calculated values are compared to verify the rationality and validity of the improved calculation module. The improved calculation module is applied to the actual calculation to analyze the influence of subway tunnel excavation on the ancient canal. Result &Conclusion: It is proved that the improved computing module is reasonable and effective. The coupling effect of seepage and stress in the tunnel section under the ancient canal cannot be ignored. The greater the initial moisture content of soil, the greater the permeability coefficient. The tunnel construction causes the overall sinking of the ancient canal and partial structure twist, so the construction protection measures need to be taken.