With the rapid development of society, it becomes a tendency to guarantee the safe train operation, improve the ride comfort and reduce energy consumption as well. Therefore, a holistic automatic train control system is of great significance. The core of automatic train control system lies in establishing an effective train model and designing an appropriate speed tracking controller. This paper introduces the main components and basic principle for automatic train control system. Then the dynamic modeling methods and speed control ap- proaches for trains are mainly induced and analyzed. Finally, the future research trend is presented.