Abstract: FLAC^3D strength reduction method is a useful method to analyze slope stability.It analyzes the influence of cohesion，internal friction angle，elastic modulus，Poisson’s ratio，dilatancy angle and tensile strength to calculation results based on strength reduction method with uniform design experiment method. The experimental results show that elastic modulus，Poisson’s ratio，dilatancy angle and tensile strength don’t have deep influence on the calculation results，especially elastic modulus，Poisson’s ratio and tensile strength，they almost have no influence on the calculation results；Cohesion and internal friction angle have great influence on the calculation results，and the influence of internal friction angle on the calculation results is greater than the influence of cohesion.This conclusion can be used as the basis of revising strength reduction factor to improve the strength reduction method.