In order to adapt to the requirements of the development for precision agriculture technology, making the rice seed tape planting technology has been widely used. The paper-making improved the design on the rice seed tape twisting machine especially the seed tape winding units. It proposed seed tape winding automatic control system based on STC90C514AD to realize the rotating speed adjustment of the seed tape disk, used an angular displacement sensor real-time detecting on the disk diameters during the winding process. The system can make the rotating speed reduce when the diameters increase. The experimental results show that the machine performs well. Coefficient of variation of the seed rope linear velocity was 4.64%, the tension uniformed during the seed tape winding process. The working efficiency of the machine is 360m/h. It shows that the machine and the control system meet the overall design requirements well.