Variable helix cutter can reduce the location error of the finished surface,leading to a more accurate machining operation.Considering the geometries of variable pitch and helix angle,and the piecewise continuous regions of the cutting,an analytical model for predicting the cutting force for milling process with variable helix angle cutter is presented.The validation of the proposed model is conducted via some cutting tests.Based on proposed model,the influence of variable helix character on cutting force is studied.Analyses show that cutting force coefficients obtained from the traditional cutting tool could be used to accurately predict the cutting forces of the variable helix cutting tool.The bigger helix angle corresponds to the smaller cutting force and bigger width of phase.The character of variable-helix angle has more significant influence on cutting force when axial depth of cut is larger.