Abstract: Following a brief introduction to the factors that impact the stability of coal preparation automatic control system, the paper presents a detailed analysis of the mechanisms of the interference effect as well as the harms that may pose to the automatic control system caused by the disturbing factors. In order to enhance the anti-interference capability and reliability of coal preparation plant automatic control system for ensuring safe and reliable operation of the plant, the corresponding anti-interference measures that need to be taken in the aspects of hardware design and software program are respectively proposed. Finally, the remarkable effect obtained in field application of the anti-interference technology in coal preparation plants is introduced, which may serve as a reference for the coal preparation plant automatic control system designers and relevant operating and managerial personnel.