The problems of large time delay, high inertia, and parameter uncertainty of the spraying and drying temperature control system in the automatic production line can easily lead to the instability of the system and the deterioration of anti-interference ability. Therefore, a control method based on the active disturbance rejection control (ADRC) is presented to improve the temperature control performance of the spraying and drying process in the production line. In this paper, a nonlinear ADRC temperature controller is designed, consisting of the tracking-differentiator (TD), the extended state observer (ESO), and the non-linear state error feedback (NLSEF). The ADRC controller does not rely on accurate spraying and drying process models, and it can solve the problem that the spraying and drying temperature is affected by various internal or external disturbance factors on the controlled system. Therefore, the temperature control performance of the system is improved. Simulation results show that compared with the traditional PID controller, the designed ADRC controller achieves high performance in dynamic performance, robustness, and disturbance rejection.