In order to study the deformation and internal force of concrete lining structure of expansive soil trapezoidal channel in northern Xinjiang, indoor test and numerical simulation were used to calculate expansive deformation of foundation soil. Based on the beam theory of elastic foundation, a mechanical model was established to calculate the deformation and internal force of concrete lining slab. The deformation and internal force of concrete lining slabs were calculated and analyzed after the operation of the channel with the initial moisture content of the foundation soil being 6%, 9%, 12% and 15%. The results show that the deformation and internal force of the concrete lining plate increase with the decrease of the initial moisture content of the foundation soil. When the moisture content of the foundation soil is 6%, the maximum expansive deformation of the channel floor and slope plate can reach 3.48 cm and 3.94 cm. When the initial water content is constant, the expansion reaction force is the largest at the foot of the slope, and the displacement and bending moment are the largest at the middle of the bottom plate. The displacement of channel slope plate is the largest at one third of the slope foot, and the bending moment is the largest at one sixth of the slope foot. Finally, according to the research results, two engineering measures of "anti-seepage and moisturizing" were proposed.