Abstract: Based on the industrial PC and multifunction data acquisition device,the control system for anchor chain flash butt welder was developed using Visual Studio Net 2003 and Measurement Studio,which could control the flash butt welding process in real time,manage the welding parameters,record the welding processes and etc. A dual closed-loop control that consists of industrial PC,high-precision displacement sensor,servo valve PID motion control module and servo valve was established to realize precise control of the electrodes. In order to avoid electromagnetic jamming,the methods including opto electric isolating,software and hardware filtering have been used. The results show that this system can precisely control the welder electrods motion,and the anchor chain welding quality is stable.