Abstract: With concentrated leakage passages linearized and the locations parameterized, a temperature analytic formula for multi-passage leakage is established. The optimum solution to locations of leakage passages is got by use of inverse analysis. In case study, the two-dimensional temperature detection model for linear leakage passages is set up by simplification. Firstly, the location of single concentrated-leakage passage is calculated by optimization. If the SSE is less than the specific value, the calculation is terminated. Otherwise, the location of the next concentrated-leakage passage is calculated and so on until the SSE is small enough. Two intense-leakage passages are located and three slight-leakage passages are roughly located at the left abutment of Douhe Reservoir in this calculation. The proposed method is more accurate than the qualitative investigation such as isotopic tracer. It indicates that the method is effective that the leakage loss of water in Douhe Reservoir distinctly decreases after the abutment is repaired.