In this paper, a facial sketch system based on real-time video is presented. This system automatically synthesizes facial edge sketch by tracking facial main control points (MCPs) accurately. There are four key steps in the system. First, dozens of main control points are obtained from frontal face image by Active Appearance Model (AAM). Second, when face moved or rotated, the new positions of MCPs are computed with optical flow algorithm. Third, face rotate matrix is obtained by considering spatial coherence and time coherence of MCPs. In the last step, cubic B-spline interpolation is introduced to connect the MCPs smoothly for sketch synthesis. Experiments shows our system has good real-time performance, and can get good results when face moved or rotated.