Abstract: Paul ion trap is an important experiment equipment to store and study ion without Zeeman effect infection by magnetic field. Based on the structure of Paul ion trap adopted in experiment and the distribution character of electric field, this article educes the ion movement equation and resolves the equation, analyzes ion motions and ion storage stability, finally summarizes the study of ion motion. It is concluded that the movement in Paul ion trap is a resonance motion, primary frequency vibration and high-level frequency vibration.

Key words: Paul ion trap, resonance motion, stability