Abstract: Leakage is the key factor affecting the safety of lakes and reservoirs, its accurate and effective detection has always been a technical problem in the field of hydraulic structure safety.Unlike electromagnetic theory based on geophysical detection technology, the single-borehole dilution technology based on the well-flow theory can directly obtain the aquifer parameters related to the seepage field without additional parameter conversion.However, traditional single-borehole dilution tests often only qualitatively judge the leakage at a point, and there are few quantitative analysis applications for detection under a large area.Therefore, we used the single-borehole dilution velocity measurement principle to investigate the leakage problem of an artificial lake in southwest China.The single-borehole dilution test was conducted after drilling near the artificial lake, and the drilling flow rate was obtained by monitoring the NaCl solution conductivity data.By analyzing and interpreting the flow rate data, it was found that the largest leakage channel of the artificial lake was located in the depth range of 420～440 cm in the ZK6 to ZK7 area and the depth range of 300～400 cm in the ZK8 area on the left side of the lake, with a drilling profile seepage flow of 4.24 cm3/s.Field experiments show that the single-borehole dilution method can not only qualitatively analyze the spatial location of the leakage channel, but also calculate the parameters of velocity and seepage flow.This accurate and efficient technique can be applied to the leakage detection of lakes and reservoirs.