Gray correlation model can be applied to the sensitive factor analysis of landslide stability; but the traditional approach for computing gray relational grade

which is based on average values

may obliterate information of the specific characteristics of gray coefficients

and possibly make miscalculation of the order relationship with whole approximation. The norm gray relational grade has a better approximation than the traditional approach; and it can express the specific characteristics of gray correlation coefficients. The norm gray relational grade is used to analyze sensitive factors that control the stability of the landslide; and the weight coefficients of each sensitive factor can be calculated. A case study of Tutaizhen landslide in Chongqing Municipality indicate that the shear strength parameters of the sliding surface are the key factors influencing the stability; and the actions of the earthquake and the groundwater are nonessential to the stability of Tutaizhen landslide.