In order to suit the large-scale efficient and environment-friendly sand blasting and rust removing for large splicing weld of hull plate, an efficient dust-free rotary sand blasting device with a large chamber and multi guns is developed. The gas-solid two-phase flow characteristics are also studied. The whole sand blasting process is placed in a closed chamber with a diameter of more than 100.0 mm. The single/double sand blasting guns are used for sand blasting on the workpiece surface through rotating the sand blasting guns at high speed with the motor. Based on the vacuum negative pressure, the rebound abrasive, eroded rust, greasy dirt, dust, etc. are recovered, separated, and recycled. A discrete phase particle model based on Euler-Lagrange method is used to numerically simulate the gas-solid two-phase flow field under different working conditions. The wear of corner joint, erosion effect of workpiece surface, abrasive deposition, and recovery effect are evaluated respectively. The simulation and real ship rust removing application show that: when the sand blasting distance is more than 100.0 mm, the abrasive particle size is 0.6 ~ 1.2 mm, the air pressure is more than 0.50 MPa, and the negative pressure is more than —0.05 MPa, large splicing welds with more than 100.0 mm rust removing width can obtain the better rust removing effect, and the rust removing quality can meet the painting requirements of Level Sa 2.5.