Presented in this article is a new accurate tool swept volume generation algorithm based on a generalized cutter for five-axis NC simulation and verification. Based on the surface envelope theory and the differential geometry, using analytical method, the strict deduction process of critical curve equation and swept envelope equation for generalized cutter are given. The motion feature of the cutter in five-axis machining is analyzed and the moving frame is established; Then, the detailed solving method of the cutter’s velocity is presented. Further, the accurate swept volume expression method and generation algorithm for generalized cutter are achieved. At last, the correctness and efficiency of the algorithm is verified by a fillet-end cutter’s experimental result.