On the basis of mechanical indexes of cooked rice grain, the taste quality of brown rice was evaluated by principal component analysis method. The main mechanical indexes of 7 varieties of cooked rice grain were determined from the specimen correlation matrix. According to more than 80.8% of the cumulative variance proportion, the two principal components were established for reflecting the taste quality of brown rice. Finally, the principal component values of varieties were obtained and the taste quality was analyzed. The results are similar to practical phenotypes, and it shows that the method of principal component analysis is more exact and feasible by the mechanical indexes of cooked rice grain. 