Abstract: The study on relative fatness(K) and weight/length index(K_wl) of wild and domestic Rana chensinensis indicates that the K value of wild female R. chensinensis had no marked difference among different age groups, but that of male was opposite between sub-adult and adult groups; K didn't change evidently in different sex groups except the adult age groups. K_wl became larger with increasing age, and had a notable sex difference in all groups of wild R. chensinensis. The K value of one-year old domestic R.chensinensis had no evident change in variant sex groups, but K_wl had. Compared with that of the same age and same sex wild R.chensinensis, the K_wl value of the domestics was higher, but K had no evident difference. Because of K_wl being more sensitive than K in statistics, it is reasonable to use both of the two indexes to study the relative fatness of amphibian.

Key words: Rana chensinensis, Relative fatness, Weight/length index