The typical fieldriges on the purple soil sloping farmlands in the Three Gorges Reservoir area were chosen to study the effects of reinforcement materials on soil shearing strength of fieldriges by laboratory unconsolidated undrained triaxial compression tests. The test results indicateds that:(1) The three tested materials showed that soil cohesion increased first and then decreased with the increasing of reinforcement amount. The cohesion of the fieldriges with different reinforced materials followed the order of c_{wheat husks} > c_{bamboo wool} > c_{rice straw} > c_{unreinforced soil}. When the cohesion of fieldriges soil was the largest, the reinforcement amount of wheat husks, bamboo wool and rice straw were 0.8%, 0.5% and 0.3%, respectively. But the effect of reinforcement materials on soil internal angle was not obvious. (2) Compared with unreinforced soil, the shearing strength of fieldriges soil with reinforcement materials all increased. As the reinforcement amount increased, the limit principal stress difference increased and then decreased, and the maximum of the limit principal stress difference all appeared at the optimal reinforcement amount of wheat husks, bamboo wool and rice straw respectively. Under the four kinds of confining pressures, the maximum value of the limit principal stress difference of reinforced fieldriges soil all showed that (σ₁-σ₃) _{wheat husks} > (σ₁-σ₃)_{bamboo wool} > (σ₁-σ₃)_{rice straw} > (σ₁-σ₃)_{unreinforced soil}. (3) Under the optimal reinforcement amount, the deviatoric stress-strain curves of three reinforced fieldriges soil samples all displayed a hardening type.