Abstract: The side milling of the profile walled of titanium alloy parts is generally processed with solid carbide end mills. Due to the influence of cutting forces, the machining process is difficult to control and will produce part deformation. Modeling and predicting of the milling forces is an effective method to control the machining deformation. Through the summation and synthesis of micro element cutting force vector of cylindrical spiral end mill, the transient cutting force prediction model in the side milling process of integral end mill was established. Both the shearing and ploughing force coefficients of the cylindrical spiral end mill for titanium alloy side milling test were obtained by using the milling force identification test under different feed speeds and the numerical linear fitting of the average cutting force test data. The instantaneous cutting forces of four edge solid carbide end mills with different cutting parameters were calculated, and the validity of the simulation model is verified by the side milling experiments of titanium alloy. This will provide a theoretical basis for the formulation and optimal selection of side milling process parameters of titanium alloy structural parts.