To address the issues of poor smoothness and abrupt changes in tool posture within five-axis CNC milling,a new interpolation method was proposed,which focused on optimizing the kinematics performance of the machine tool used.Firstly,within the specified critical area of the tool path,interference-free key tool axis directions were determined.The corresponding rotary axis coordinates for these key tool axes were then yielded.Next,the displacements of the rotary axes movements were represented using a continuous B-spline curve.Linear expressions for their kinematic characteristics were then derived,and an optimization objective function was established to minimize the sum of squares of the jerk in the motion of each rotary axis.By solving the optimization model under the constraints of the key tool axes,smooth interpolation of the tool′s posture along the tool path was achieved.Experimental results show that the proposed method can achieve better kinematics performance compared to the traditional method,effectively improving the stability of the machining process.