Abstract: The chamfering machine is used for facing both ends of the seamless steel pipe to ensure the ends up to applicable standard-specified criteria. Described in the paper is a hi-prevision electrical system for centering of seamless steel pipe as being machined with the in-line chamfering machine, covering such aspects as the working principle,the design concept,the theoretic basis,the calculation formula as well as the hardware configuration and the software flow chart,etc. The actual operation result show that the said auto-centering system is capable of safe and easy operation, and features convenient maintenance and high productivity.