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Adopting two degree computers control system, the electro-hydraulics servo system of automobile leaf spring rolling mill was designed in the paper. The mathematical model of electro-hydraulics servo system, composed of the electro-hydraulics servo valve and servo cylinder and roller, was built up. On the basis of analysing the steady characteristic and dynamic characteristic of system, PID correction methods had been adopted to increase cut off frequency and decrease adjusting time and steady state error further. The result showed that electro-hydraulics servo system of rolling mill has good steady characteristic and high control precision, and it achieves the design purpose.