The underwater heat exhausting source can cause the thermal difference of the surrounding and surface water.In this paper,the thermal character caused by the underwater heat exhausting source is studied by numerical simulation and experiment.The results show that the thermal floating distance is related with the sailing velocity of the underwater target.The higher the velocity is,the longer the hot wake is,and the broader the hot scope is.The relative distance of the thermal floating spot is almost in a logarithmic law with the velocity.The experimental results are accordant with the numerical simulation,and the obvious hot wake can be observed by the moving underwater heat exhausting source testing with temperature sensors and infrared camera. The underwater heat exhausting source can cause the thermal difference of the surrounding and surface water. In this paper, the thermal character caused by the underwater heat exhausting source is studied by numerical simulation and experiment. The results show that the thermal floating distance is related with the sailing velocity of the underwater target.The higher the velocity is, the longer the hot wake is, and the broader the hot scope is.The relative distance of the thermal floating spot is almost in a logarithmic law with the velocity. the experimental results are accordant with the numerical simulation, and the obvious hot wake can be observed by the moving underwater heat exhausting source testing with temperature sensors and infrared camera.