Objective: To optimize the operating parameters of wheat milling in roller mill I skin mill to reduce the energy consumption of milling. Methods: Using EDEM discrete element simulation software, Box-Behnken test was designed for key milling factors such as roll pitch, feeding amount, rotational speed and rotational speed ratio to investigate the relationship between operating parameters and milling power. Results: The significance rankings of the effects on the toothed roll crushing power were, in order, speed ratio, roll pitch, feed volume, speed ratio quadratic term, roll pitch quadratic term, interaction of roll pitch and speed ratio, interaction of feed volume and speed ratio, and interaction of roll pitch and feed volume. According to the different requirements of the I-skin mill, the optimal parameter combinations were obtained: the finer powder output with a rolling pitch of 0.67 mm, a feeding amount of 803.60 kg/（cm·d）, a fast roller speed of 537.68 r/min, and a rotational speed ratio of 2.64, and the coarser powder output with the optimal low-power consumption of 0.79 mm, a feeding amount of 803.83 kg/（cm·d）, a fast roller speed of 576.08 r/min, and a rotational speed ratio of 2.23. Conclusion: The error between the simulation results and the measured results is within a reasonable range, and the established discrete element milling model can be used for power prediction in wheat milling.