The morphological changes of fresh beef treated with ficin(0.1% : 2 hrs, 6 hrs)were examined with transmission electron microscope(TEM), the results obtained were as follows ; Connective tissue protein in fresh beef treated with ficin became gradually fragmentation and was occured stabilization with time. The length of sarcomere in myofibrillar protein was elongated, M-line became dim, and the I-band of Z-line was broken and became fragmentation with time.