The conceptual design of high-speed train heads lacks aerodynamic performance evaluation during the early sketch design stage. To improve the design efficiency, a novel collaborative method integrating free-hand sketch with computational fluid dynamics (CFD) simulation for the design of high-speed train heads is proposed. To simulate the free-hand sketch, the sketch contour is extracted by first enhancing the sketch image, then extracting key points from the contour, and finally smoothing the key points. A CFD simulation is conducted to analyze the aerodynamic characteristics of the sketch contour, including the aerodynamic drag coefficient and pressure cloud map. In addition, a user interface is designed to integrate the contour extraction method and the CFD simulation. The effectiveness of the proposed method is demonstrated by several experiments.