Aimed at the Chinese glasses manufactures, spectacle-frame processing technology driving by three-dimensional curve was put forward. The special CAM processing software with five-axis NC machine as the target machine was designed, and the production efficiency was improved. Based on the five axis machining characteristics, calculating the cutter posture vector was became a key step to achieve at three-dimensional curve drive a CAM system. The cutter required by the cutter contact spaces was obtained, by using two rules to determine cutter posture vectors and parametric equations to solve and optimizing the calculation process. By using this method in the CAM software to generate each cutter contact posture and generate G-code, the feasibility of the method in the target machine is tested.