In order to improve the surface strength and heat-insulating capability of Ti-6Al-4V alloy, ZrO2 particles were injected into the Ti-6Al-4V surface melted by laser. In this paper, the melt-injection-interaction process was modeled using CFD method and the simulations were partly verified by experiments. In this model, the moving gauss laser was defined based on the equivalent thermal effect. VOF method is adopted to analyze phase change process and detect the free surface of molten pool. The buoyancy, inertia force and viscous drag were considered when calculating the particle movements. Temperature and velocity fields inside the molten pool were analyzed, and the influences of the convection caused by thermal-fluid coupling on particles injection and distribution were revealed. The results show that the temperature field and flow field in the molten pool are redistributed with the entry of the particles and the fluid flow and the solidification of the molten pool distribute the particles in different positions. The number of ZrO2 particles was counted per 100 μm depth, it’s found that with the increase of laser scanning velocity, particle densest positions became closer to the substrate surface.