Abstract: The stability analysis and evaluation of wedge rock mass is a difficult problem in engineering field, and there are defects in the traditional evaluation method. By the establishment of the related computer program, the various improvement to the traditional method is made, and the method of vector algebra is applied to calculate the safety factor of block model. The automatic implementation of the stability analysis and evaluation of weage rock mass are acchieved by the program. Finally, the feasibility and advantage of the improved method is verified by a real instance in engineering field, the method has considerable practical value.