Through direct shear test and unconfined compressive strength test, the paper researched the influence of water content on the shear strength index and unconfined compressive strength of the soil reinforced with wheat straw. The results show that certain water content is a necessary condition for the performance of soil reinforced with wheat straw. With the increase of water content, the cohesion of soil reinforced wheat straw shows a trend from first increase to then decrease. When the moisture content reaches the optimum, the value of cohesion reaches the maximum. However, the internal friction angle of reinforced soil gradually decreases with the increase of moisture content. Under the condition of certain water content, the optimal reinforcement rate of wheat straw fibers is between 0.1% to 0.3%.