In recent years, due to the growth of the Smartphone users, the G-sensor has already become the standard equipment on Smartphone. Besides, G-sensor can be applied to the body motion sensing and provide new communicating interface for users. However, for easy implementation of gravity sensing system, the application would usually restrict users the way of holding Smartphone. In this thesis, we propose a method that can analyze the body motion without restricting the way users hold their phones by the G-sensor of the Smartphone. In this thesis, we analyze and classify the motions of users with LMA.