Abstract: During the rolling process of seamless steel tubes, the friction coefficient of the rolling contact interface needs to be calculated accurately.Considering the shortcomings of the existing friction coefficient calculation model, in order to improve the prediction accuracy of the friction coefficient of the rolling contact interface, a nonlinear friction coefficient model capable of indicating actual rolling conditions is established.Furthermore, the parameters of the said model are optimized by means of the nonlinear optimization method and related site-measured process data as well.The result shows that the model-calculated values are in full agreement with the actually measured values, having been capable of meeting the practical needs for the production of the company.