Abstract: Based on the large scale tri-axial tests of coarse-grained red sandstone soil reinforced with double twisted hexagonal wire mesh, the reinforced mechanism, the playing process of reinforced effect, the influence of water content and reinforcement layers on the fact that the reinforced effect were studied.The results show that, due to the reinforcement can increase both the cohesion and internal fraction angle of soil, the quasi-cohesion theory is not suitable to this kind of reinforcement, its contribution to soil's internal friction angle should be considered in engineering;the effect of reinforcement on soil needs a playing process, only after the soil strain transcended a critical strain, should the really reinforced effect be brought to play.The reinforcement effect under low confining stress is better than that under high confining stress, and under the low confining stress the reinforced effect of sample reinforced with three layers steel mesh played earlier than the one reinforced with two layers steel mesh, but under the high confining pressure, it is exactly the opposite;the water content and reinforced spacing have big influence on the effect, the shear strength parameters c and of reinforced samples decreased while the water content increased, and they increased with the decrease of reinforced spacing, the empirical formula of c and with reinforced spacing and water content were gotten by multiple regression analysis.