Abstract: This paper described the primary difference of underground water existing between in term of exploration of underground water resources and control of geological disaster resulting from underground water flowing.The former considered underground water to be homogenous stratified distributing, the later to be distributing with flow vein along some tectonic weak positions. The difference between underground water temperature distributing with flow vein and normal earth temperature below surface 1m can result in abnormal temperature in measuring process. Therefore,the method to measure shallow earth temperature can be used to detect flowing underground water with depth and scale in some extent. Shallow earth temperature is influenced by surface temperature change everyday and every year, topographic change, elevation change and surface feature change, so it should be corrected. This method was carried out in Yuqiao reservoir dam, results showed that the seepage paths and parts of dam inferred were tallied well with observational data.