The discharge of sediment plumes from deep-sea mining activities has an important impact on the marine environment, in which submarine currents play an important role in the diffusion of plumes. In the present study, combined with the Volume-of-Fluid (VOF) model and the discrete phase model (DPM), the effects of ocean current on the plume diffusion around the deep-sea mining vehicle (DSMV) were numerically simulated, and the effects of current angle, ocean current velocity and plume discharge velocity on the plume diffusion range were investigated. The results demonstrate that: (1) The interaction between DSMV wake vortex and plume vortex has a significant influence on the plume discharged in the wake area; (2) With the increase of the current angle, the underside plume is skewed to the downstream side. When the current angle is 90°, part of the plume is reversely diffused to the front of the DSMV under the influence of wake vortex; (3) At high ocean current velocity, the longitudinal diffusion distance of the plume is negatively correlated with the change of current angle, and the correlation decreases with the decrease of ocean current velocity; (4) When the current angle is less than 45°, the transverse diffusion distance of the plume is positively correlated with the current angle, while when the current angle is 90°, the transverse diffusion law of the plume is different due to the change of flow field structure.