To investigate the influences of electro-acupuncture of different electro-frequencies on muscle, twenty-four male New Zealand rabbits were treated once everyday with manual acupuncture or electroacupuncture of different electro-frequencies (2 Hz, 15 Hz, 100 Hz) on acupoints as Yangling Quan (GB-34) and Huantiao (GB-30) for 15 times as one therapeutic course. Muscular tissues of the acupoints were taken at the very day of the ending and 1,2 months after one therapeutic course respectively. All muscular tissues were processed through fixation, section and stain before microscopic examination. Serum enzymes as GOT, CPK and LDH were also evaluated after the eighth acupuncture. The results showed the highest degree of bleeding, inflammatory, degeneration and necrosis in the 100 Hz EA group. In manual acupuncture group, there were changes of milder degree than those occurred in EA group. The more the muscular damage yielded, the higher the serum enzyme increased. The value of CPK and LDH in 100 Hz EA and 15 Hz EA groups were the highest. This study indicated the higher the EA frequency and the larger the dosage of acupuncture, the more severe the muscular damage yielded.