The water-cooling wall of a furnace often leaks under harsh conditions, such as high temperature and pressure, which affects the safe and economic operation of the boiler. To achieve the localization of multiple leakage sources in a water-cooling wall, an acoustic positioning method based on improved differential evolution and density-based spatial clustering of application with noise (IDE-DBSCAN) is proposed. The nonlinear equation system is constructed using the time delay of arrival (TDOA) obtained by the generalized second cross-correlation algorithm, and the IDE algorithm is used to solve the nonlinear equation system and obtain multiple spatial positions corresponding to multiple TDOA sequences. To eliminate false leakage sources, IDE-DBSCAN is presented to cluster multiple estimated positions. The number of clusters obtained is the number of leakage sources, and the cluster centers are the location coordinates of the leakage sources. The numerical simulation results show that, compared to traditional acoustic positioning methods, IDE-DBSCAN has a higher positioning accuracy and better anti-noise ability. In addition, experiments are conducted on multiple leakage sound sources within a measurement area of 1 m × 1 m × 1.06 m, and the positioning errors remain within 5 cm. The proposed method provides a theoretical basis and experimental verification for further research on the localization of multiple leakages of water-cooling wall in furnace.