Abstract: The paper deals with 7 growth indices of Mandarin vole (Microtus mandarinus Milne-Edwards) by the principal component analysis,such as weight,body length,body weight excluding viscera,tail length,length of hint foot,greatest length of skull and zygomatic width.The results are as follows:the growth indices of skull are the leading facters in all indices with the highest contribution rates (99.24%,99.16%) for the correlation matrix.Length of hint foot and body weight exduding viscera are in the second level.The correlativity of weight and the growth of the vole is lower,as well as body length which contribution rate is negative value.Based upon the necessity of precision and operation,the authors suggest that weight excluding viscera is the best indicator in the age determination of Mandarin vole.