Abstract: In this paper, the shear strength characteristics of rubber-reinforced unsaturated expansive soil are studied, the effects of the size and content of rubber on the deviatoric stress, failure strain, shear strength parameters, internal friction angle and cohesion of unsaturated expansive soil were studied by unconsolidated undrained(UU) triaxial test. The test results show that the mixing effect of 80 mesh rubber is better than that of 60 mesh rubber, and 5% 80 mesh rubber can increase the peak strength of the expansive soil. The peak strength of ESR decreased with the increase of rubber content, and the decrease of peak strength depends on the decrease of cohesion. It should be noted that the failure strain of ESR increases with the increase of rubber content, i.e. the increase of plasticity and the decrease of stiffness of expansive soil are mainly caused by the addition of rubber. The different appearance of ESR depends on different test methods, different soil types and different rubber reinforcement forms. Under the test conditions of this paper, adding 5% 80 mesh rubber powder is the best choice for improving the plasticity and strength related properties of expansive soil.