The Gujiao Reach of the Fenhe River in the Jinci Spring basin is in the mountain valley. The most parts of the valley is of exposed soluble rock strata of Cambrian-Ordovician carbonate rocks. The seepage of the river is considerable. Based on the measured data from the experiment cross section. A leakage coefficient model was established for the section flow of the upstreram leekage reach This paper also analyzed the leakage patterns over sections along the stream, and calculated the leakage vlolume.