Five-axis NC machining provides a valid and efficient way to manufacture the mechanical parts with complex shapes,which are widely used in aerospace,energy and national defense industries. Its technology innovations have attracted much attention in recent years. In this paper,the state-of-the-art techniques for five-axis machining process planning are summarized and the challenging problems are analyzed from the perspectives of tool path generation,integrated geometric/mechanistic simulation and machining stability analysis. The recent progresses in accessibility-based tool orientation optimization,cutter location (CL) planning for line contact and three-order point contact machining,shape control of cutter envelope surface and milling stability prediction are introduced in detail. Finally,the emerging trends and future challenges are briefly discussed. Five-axis NC machining provides a valid and efficient way to manufacture the mechanical parts with complex shapes, which are widely used in aerospace, energy and national defense industries. Its technology innovations have been much more attention in recent years. In this paper, the state -of-the-art techniques for five-axis machining process planning are summarized and the challenging problems are analyzed from the perspectives of tool path generation, integrated geometric / mechanistic simulation and machining stability analysis. The recent progresses in accessibility-based tool orientation optimization , cutter location (CL) planning for line contact and three-order point contact machining, shape control of cutter envelope surface and milling stability prediction are described in detail. Finally, the emerging trends and future challenges are briefly discussed.