The present invention discloses a blind information based talus slide safety evaluation method. The method comprises the steps of: defining cohesion and an internal friction angle as blind information parameters for talus slide safety evaluation; selecting sliding zone soil samples to carry out a direct shear test, obtaining blind information data of each sample, and by data processing, respectively obtaining a preliminary expression of cohesion blind information A and internal friction angle information B; using a trapezoidal fuzzy number to simulate and characterize blind information, using an alfa cut technique to carry out quantitative processing on the trapezoidal fuzzy number, and respectively obtaining a final expression of the cohesion blind information A and the internal friction angle information B; by using a rigid body limit equilibrium method, constructing a blind information model of talus slide safety evaluation, and obtaining an expression C=A*B of safety factor blind information C; and according to the expression of the safety factor blind information C, carrying out evaluation on talus slide safety. The method disclosed by the present invention combines a blind information theory and the rigid body limit equilibrium method, and can provide more comprehensive unstable landslide information for engineering and technical personnel.