In order to overcome the shortcoming of ignoring the displacement delay for the traditional rolling mill main drive system, a model of nonlinear displacement delayed feedback system in the rolling mill main drive system is derived that considers friction, damping, stiffness and delay. The local stability of the system and the existence of Hopf bifurcation are analyzed, and the delay threshold is drawn theoretically. The correctness of the model is verified by simulating and contrasting between the blooming mill experimental data of 1 150. The time-history chart, phase diagram and bifurcation diagram of the displacement delay feedback system in the rolling mill main drive system are achieved simultaneously, and time delay is proved to be a bifurcation parameter. When the time delay exceeds the threshold, the system generates Hopf bifurcation. In conclusion, delayed adverse effects in the production process can be avoided by increasing the rolling speed, which suggests a new idea for further study on how to control the rolling mill drive system.