The three-dimensional entity model of the case of mine reducer was established by Pro/E software,and a finite element analysis on the structure of the case of mine reducer was carried out by ANAYS software,and the most unsubstantial part in the reducer case was found.Based upon the finite element analysis,the reducer case had been optimized,so that the materials for manufacturing single reducer case was reduced by 523 kg,the cost of its production was reduced by 16.3% in manufacturing materials.