Abstract: In order to study the wear mechanism of star wheel of TBM during loading, based on discrete element method and wear theory, the wear simulation model of TBM star wheel during loading is constructed in EDEM software by combining Hertz-Mindlin contact model and Archard wear model. The wear of the star wheel at different speed and number of teeth is analyzed. The results show that: the wear of the star wheel increases with the increase of tooth number and speed. The wear range of the left and right star wheel is 16.4 μm, 23.8 μm, 13.1 μm, 18.3 μm, and the maximum wear increment range of the left and right star wheel is 0.5 μm, 2.8 μm, 0.6 μm, 3.2 μm, respectively. The tooth area of the star wheel has the most contact with coal falling, and the wear amount is also the largest. The wheel hub part is less than the tooth because it is only impacted by partial coal falling. The difference of the maximum wear of the star wheel under the conditions of fixed number of teeth and fixed speed is 8.4-11.5 μm and 7.5-12.7 μm, respectively. The comparison shows that the number of teeth of the star wheel between the two conditions is the main factor affecting the wear of the star wheel.