Abstract: Introducing time series analyses method,this paper takes Tongluoshan long tunnel,constructed in a kar-stic area,as an example,quantifying its response characteristics to the precipitation by adopting correlation and spectral analysis.Resultsof this research indicate that the groundwater system has huge storage capacity in the tunnel region with strong regulation and filtering ability,which results in low correlation found between the tunnel inflow and precipitation but with a lag about 12.62 d,concluding that the connectivity between precipitation and tunnel inflow is very weak.These results can offer scientific basis to the prevention and drainage of tunnel inflow.