Fiber placement technology is key to producing composite structures, and it is also the fastest growing and most efficient composite manufacturing technology. Control of tows increase or decrease is the focus in the study of a placement control system because the tow placement of a fiber placement machine is mainly performed by the fiber placement head. Through analyzing the operating cycle of a single tow and the operating mode of the clamp, the restart and cut module in tows restart, the cut and fiber placement working condition, fundamental principles of program designing are proposed. A comprehensive approach of tows increase or decrease and motion control is presented together with an independent approach of tows increase or decrease and motion control. A comparison of these two control schemes shows that the second scheme is more convenient and practical. Finally the experiment results demonstrate that this method is valid and efficient.