The Eulerian multiphase model and continuum surface force (CSF) are employed to simulate the liquid droplet impinging onto a solid wall with a pre-existing thin film of the same liquid. The numerical results are compared with the experimental data reported in the literature, indicating a reasonable matching. The flow field and splashing behavior of a droplet impinging onto a liquid film are analyzed. The reason for the edge of the crown to eject into secondary drops is found. The splashing behavior can be influenced by the impacting velocity and fluid properties. The effects of impact velocity, droplet diameter, depth of film, liquid property, and droplet and wall temperature on the heat removal are investigated. Numerical results demonstrate that an increase in impact velocity, droplet diameter, film depth, cooling droplet, and wall temperature enhances the dissipated heat. These results can provide a reference for designing spray-cooling systems.