Abstract: A milling unbalance correction method based on a discrete vector model is proposed to address the issue of poor performance of traditional dynamic balancing methods when the initial unbalance of the micro motor rotor is large. A discrete vector model is established based on the parameters of the milling cutter and rotor， and the corresponding relationship between the equivalent cutting mass and cutting depth under second time cutting is obtained by integrating the discrete points of the edge curve. By comparing with the 3D model simulation data， it is verified that the deviation rate of the model is low. Experimental verification shows that when the initial unbalance on one side of the rotor exceeds 100 mg， a total weight removal rate of over 90% can be achieved， and the equivalent mass of the remaining unbalance on one side can be controlled below 10 mg. All rotors meet the G1 accuracy level. This indicates that this proposed method can improve the dynamic balance accuracy of the micro motor rotor when the initial unbalance of the micro motor rotor is large.