The processing of constant elasticity alloy demands higher surface quality and machining accuracy.In order to achieve the precise and quantitative removal of constant elasticity alloy,a new machining method using femtosecond laser ablation was explored.Firstly,the ablation threshold of constant elasticity alloy material was calculated and analyzed under the irradiation of high intensity femtosecond laser;secondly,the effect of femtosecond laser pulse energy and pulse number on diameters and depths of the ablated micro craters was experimentally studied.The experimental results show that:the femtosecond laser ablation threshold of constant elasticity alloy is 0.167 J/cm2;the ablation diameter increases with the increasing of pulse energy,and the ablation depth increases with the increasing of pulse number.The maximum of femtosecond laser pulse ablation diameter is 150.64 μm,and using femtosecond laser trepanning method,a micro hole with diameter of 500 μm is obtained,which improves the ability of femtosecond laser ablation process.