Due to the large difference between the heat dissipation rate of water and air, water leakage on the wall surface after rainy days or artificial sprinkling of water will be deposited in the infrared thermal imager in a low-temperature area. By analyzing the infrared images of sunny and wet walls, leaks can be found and repaired in time. The use of infrared camera for external wall water leak detection is faster than conventional detection methods. A single person can operate conveniently and quickly.