Abstract: In cesium frequency standards,the output frequency are sensitive to microwave amplitude because of the effects of Rabi pulling,Ramsey pulling and microwave cavity pulling in the tube.Based on the mechanism of the effects of microwave amplitude on output frequency,and relationship between microwave amplitude and transition probability,this paper proposes a method to reduce the sensitivity of output frequency to the microwave amplitude variation.Experimental results show that this method can reduce the effects of microwave amplitude variation on frequency accuracy and long-term frequency stability effectively.