The purpose of this study was to investigate the intensity-specific regenerative effects of microcurrent therapy on gastrocnemius muscle atrophy induced by cast-immobilization in rabbits. Fifteen rabbits were randomly allocated to 3 groups after cast removal: cast-immobilization and sham microcurrent therapy for 2 weeks (group 1); cast-immobilization and microcurrent therapy (25 μA) for 2 weeks (group 2); cast-immobilization and microcurrent therapy (5,000 μA) for 2 weeks (group 3). Clinical parameters [calf circumference, compound muscle action potential (CMAP) of the tibial nerve, thickness of gastrocnemius muscle], cross sectional area of gastrocnemius muscle fibres, and immunohistochemistry was evaluated. The clinical parameters representing mean atrophic changes in group 2 were significantly lower than those in group 3. The cross sectional area of the gastrocnemius muscle fibres and immunohistochemical parameters in group 2 were significantly greater than those in group 3. The results showed that low-intensity microcurrent therapy can more effectively promote regeneration in atrophied gastrocnemius muscle than high-intensity microcurrent therapy.