It is difficult to give a definitive evaluation result when using the fuzzy probability method to evaluate the three-dimension (3D) slope and to develop an effective method is necessary to evaluate the stability of a large number of 3D slope engineerings. To solve this problem, a novel method of 3D slope stability analysis is proposed based on renormalization group and response surface function. After determining the critical instability probability of 3D slope based on the theory of renormalization group, the response surface method is employed to construct a function to solve the fuzzy instability probability of the 3D slope. Then the stability of the 3D slope can be determined by comparing the critical and fuzzy instability probability values. When the fuzzy instability probability is less than the critical instability probability, the 3D slope is in stable state, otherwise it is in unstable state. The novel method for 3D slope stability analysis is verified by the mine dump slope engineering. Results show that the proposed novel method is accurate and reliable. This study solves the problem of quantitative evaluation of 3D slope stability and the conclusions obtained in the study are of important reference value to direct similar engineering practice. Keywords: 3D slope, Renormalization group, Fuzzy probability, Stability analysis