Abstract: The problem of fluvial-thermal erosion of artificial frozen soil during the process of ground freezing disasters is conceptually defined, and its essence is the determination of the position of the double-moving boundary. The self-developed indoor simulation test device for the erosion of frozen soil is used to study the problem. The test device and the arrangement of measuring points are introduced, and the quantitative judgment standard for the double–moving boundary is given. Three main factors affecting the fluvial erosion are selected: water flow velocity, initial temperature of frozen soil and moisture content of soil. The control variable method is used to group the tests. The movements of the double boundaries over time under different conditions are obtained. It is found that the movement rate of the double boundaries shows a two-stage change pattern with the flow velocity. The movement rate increases rapidly and then slows down, indicating that the existence of the frozen soil greatly slows down the erosion rate. Under three different temperature conditions, the movement of erosion boundary is basically the same, indicating that the initial temperature of the frozen soil has few influences on the boundary movement. Whether the soil is saturated or not has a great influence on the movement of erosion boundary, and the corresponding erosion rate when the soil is not saturated is obviously greater than that when it is saturated.