Hydraulic thrust system is a critical part of shield tunneling machine. Automatic trajectory tracking control is a significant task of thrust system during tunnel excavation. In this article, plane mechanical structure diagram of the thrust system and path planning method are illustrated at first. An integrated control system is proposed to achieve the automatic control of the thrust trajectory. The control system consists of one trajectory planning controller for both cylinders and an individual cylinder controller for each of hydraulic cylinders. Trajectory planning controller is used to generate respective displacement signals of double-cylinder in every thrust stroke and each of cylinder controllers is used to realize the precise control of the given thrust trajectory. Variable-gain PID control strategy applied to achieve the precise tracking control of thrust trajectory under several typical working conditions are done at last. The experimental results demonstrate that variable-gain PID control have good performances with short response time and small overshoot regardless of changes of working conditions.