To improve the stability of the high order harmonic components,regeneration mode locking control is used as a solution.Firstly the formation mechanism of the mode locking pulse is analyzed.Then optical frequency synthesis is made based on three wave transient state coupling equation.Finally the high order harmonic components are obtained.In the experiment,pulse image obtained is balanced and the mode locking pulses are smooth.High signal-tp-noise ratio and high stable amplified light is obtained,which increases the quality and flexibility of chirp pulse amplifying system.The analysis method presented can be also applied to the design of other stable light source.