The measure of reinjection is an important technical measure to solve the water level drop of geothermal water and realize the sustainable utilization of geothermal resources. However, at present, there are some problems in the reinjection development of carbonate fracture thermal reservoir, such as the law of reinjection seepage is not clear, and the mining mode of reinjection is not clear. The seepage law of reinjection in carbonate fracture thermal reservoir is complex, and the relationship between the seepage of reinjection in fracture and karst cave, the injection direction of reinjection and the development direction of fracture is not clear. Therefore, according to the pore structure characteristics of the target carbonate fracture thermal reservoir, micro fracture etching model and emented fracture plate model are used to study the influence of injection speed, injection direction and well pattern mode of reinjection water on the micro seepage law. In the micro etching model, when the fracture orientation is 90 ° and the injection velocity is 0.04 ml/min, the sweep area of reinjection is the largest. By increasing the injectionrate and the fracture azimuth, the reinjection water wave and area can be increased. Based on the micro etching visualization experiment, the temperature field of reinjection water injection is studied by using the physical model of carbonate fracture thermal reservoir cementation. The sweep area of the temperature field and the seepage route of the backwater are basically the same as those in the micro etching plate.