Abstract: During a loss of vacuum accident (LOVA), dust migration is related to the safe operation of fusion devices. The study of dust migration and its influencing factors helps to eliminate or alleviate the risk of accidents caused by dust. The computational fluid dynamics (CFD) was used to simulate the dust migration during LOVA. Based on the STARDUST numerical model which has proved to be valid, the dust migration model was built and the gas flow state and the dust migration characteristics during LOVA were reproduced. Through changing the physical properties of dust, break positions and the existence of obstacles, the influence factors were studied. It is found that the distribution of dust in the vacuum vessel (VV) is more similar to the velocity field of gas when the diameter and density is smaller. The simulation results also show that during LOVA, the dust distributions in VV are different when the break positions vary and the existing of obstacles can limit the migration of dust obviously.