Abstract: In order to observe the proportion and the distribution of fibe types in the gastrocnemius muscles and tibialis anterior muscles, histochemical characteristics of the muscles fibers from adult rabbits were observed by nicotinamide adenine dinuclectide tetrazolium oxidoreductase (NADH-TR) staining. The results revealed that these muscle fibers were divided into type I，IIA and IIB fiber，and showed a mosaic pattern of fiber types distribution. The percentage of type I，IIA and IIB fibers were separately 15.2% , 27.4% and 57.4% of the total amount of medial gastrocnemius muscles, and about 13.7% , 65.4% and 20.9% in lateral gastrocnemius muscles. We suggeste that the medial gastrocnemius produce relative high tension in maintaining the standing posture and stabilizing organism, and the lateral gastrocnemius serve more in velocity and force. In the tibialis anterior muscles, the percentage of I，IIA and IIB fiber types are about 10.9% , 52.3% and 36.8%. It is designed mainly to stabilize the ankle and to help to maintain the arches of foot, and take part in plantarflexing the ankle. The diameter of type I fiber was among 57.50-58.40 μm, type IIA fiber was among 59.25-75.40 μm, type IIB fiber was among 73.25-97.85 μm in medial gastrocnemius, lateral gastrocnemius and tibialis anterior muscle. Transverse section of type IIB fiber was the biggest, transverse section of type IIA fiber was medium, and transverse section of type I fiber was the smallest.