Abstract: The deformation failure mechanism and shear strength characteristics of reinforced filling soil in Wushan county are studied with triaxial apparatus.It is shown that the shear strength of the reinforced soil is higher than that of the unreinfo rced soil,but the frction force between geotextile band and soil is quite weak because the surface of the geotextile band is relativly smooth.As a result,a sliding plane is formed between getotextile band and soil,and the ability to resist the slight deformation is weakened.Meanwhile,it is found tha tenclosure pressure and layers of geotextile band also can affect the shear strength of the reinforced soil.