Abstract: Muscle fiber type of skeletal muscle and its expression of the variety of the specialized protein isoform are the structure and molecular basis of the skeletal muscle's function and adaptability. Myosin heavy chain（MHC）isoform, regarded as the factor which determinates whether the type of the skeletal muscle is fast or slow，have become molecular symbol by which we can tell the muscle fiber type and study muscle's adaptability. Exercise may lead to the transform between myosin subtypes. This article makes a general review not only on the relation between myosin heavy chain and muscle fiber type of skeletal muscle, but also on the influences made by different motor patterns' upon the transform of skeletal muscle fiber MHC isoform.