In the ion beam figuring progress,good stabilization of the beam function is necessary for determining machining and is correlative with the stabilization of the ion source.To study stabilization of a kind of ion source,the progress and mathematical model of the line-scan method are introduced.The fluctuation of the beam function in different times is analyzed to show the stabilization of the ion source.The result shows that the stabilization of the ion source is great and can meet the demand of ion beam figuring(IBF) progress for optics mirrors.