We calculated the elasticplastic finite element method (FEM) of three adobe walls and three composite adobe walls of differing thicknesses, and analyzed their lateral resistance capacities, crack shapes and ductility. Based on the results, a simplified formula is put forward for calculating the lateral resistance capacities of composite adobe walls. The formula provides a basis for designing composite adobe walls. In addition, we estimated the seismic effects of earthquakes of varying degrees and frequency of intensity (basic and rare intensity) on composite adobe walls. The results indicate that traditional adobe walls with timber columns and beams can satisfy the criterion of rare earthquakes of seismic zone 9. The results provide a basis for the transformation and seismic reinforcement of traditional residential buildings in Xinjiang.