Abstract: For improving the intelligence level of accelerator, an automatic control system of electrostatic accelerator was developed by adopting PLC control technique, infrared and optical-fiber transmission technique and net communication. On the basis of introducing the control system’s structure, interference sources were analyzed and some measures against interference are adopted. The measures in hardware include restricting the position of corona needle, using surge arresters, shielding, connecting ground and stabilizing voltage; the measures in software include inter-blocking protection, soft-spacing, time delay and diagnosis protective program. These effectively improve the electromagnetic compatible ability of the control system. The system works steadily at present. The breakdowns don’t happen again except that signals are lost occasionally.