A system and a method for detecting a muscle activity are provided. The system includes a vibration detector. The vibration detector detects a vibration signal at a sensing point located at an opposite side of an operating muscle system for analyzing a body movement.一種肌肉活動辨識系統與方法。肌肉活動辨識系統包括一震動感測器。震動感測器於一作用肌系統對側之一量測點,感測一震動訊號,以供分析一肢體動作。