Abstract: As the lined channels in Northwest China are subject to frost heave soil extrusion damage in winter, coupled with the easy sinking of wet-submerged loess in water, the frost damage of lined channels with wet-submerged loess as foundation is complicated. To address this problem, this paper takes the East First Trunk Canal before and after the renovation of Ningxia Guhai Irrigation District as a prototype, and establishes a simplified three-phase coupled mathematical model of the channel by analyzing the deterioration law of the channel before and after the renovation by frost damage and the plastic damage structure of concrete material. Considering the mechanical properties of wet-submerged loess and the contact behavior between canal base soil and liner plate, the numerical model of thermal-force coupling of lined channels before and after renovation is constructed by ABAQUS software based on the measured data, and the specific situation and deformation law of frost swelling are simulated and analyzed in comparison. By comparing the three physical fields simulated by the two coupled models, the results show that the frost damage of the modified rigid-flexible lined channels has been substantially improved and the stress concentration has been avoided to a certain extent; comparing the field data before modification with the research results, the accuracy and feasibility of the numerical coupled model are verified, and the three physical fields of heat-force-displacement simulated can better reflect the frost swelling mechanism of the actual lined channels, which serves as a reference for the management and modification design of the frost damage of the irrigation channels.