Abstract: The consolidated-drained triaxial tests were carried out on clayey soil reinforced with geosynthetics to investigate the influences of reinforcement on the performances of the volume strain, the strength and the stress-strain characteristics in the paper. Results showed that reinforcement had restrained remarkablely the volume swell of soil with high compactness, but influenced on the volume shrinkage insignificantly. At lower axial strain levels, the strengths of reinforced soil were even smaller than that of the unreinforced. Only when increasing the axial strain, the strengths of reinforced soil exceeded gradually, the reinforcement contributions to the strength is delayed. Results also showed that when the reinforcement modulus was too low, although the increasing layers might increase a little the peak strength of soil, the post-peak strength was improved insignificantly. By comparision, the increasing modulus enhanced the residual strengths more significantly than the peak strengths of soil, and the stress-strain behaviors of clayey soil were improved remarkablely.