A instantaneous milling force prediction method considering of the curvature,the lead angle and the tilt angle,is proposed for sculptured surface mould machining. In view of geometry features of the sculptured surface,the impacts of the curvature radius on feed direction and cross feed direction on cutting angles are explored. Furthermore,the impacts of the lead angle and axial tangential angle on the undeformed chip thickness are studied. By means of differential theory,the cutter-workpiece contact area in arbitrary rotation period of sculptured surfaces machining is discretized. Based on the 3D trochoidal tooth trajectory,the model of the undeformed chip thickness is established and the instantaneous milling force considering of the curvature features and cutting angles is obtained for three axis ball end milling of sculptured surfaces. Finally,experiments of machining mould with quadric surface are conducted to measure the milling force. The estimated milling forces match well with the actual cutting forces obtained from experiments. The error rate of estimated instantaneous milling forces is approximately 12%,which verifies the efficiency of this method to estimate the instantaneous milling force in milling of sculptured surface mould with sculptured surfaces.