Sweeping sand technology is a new surface treatment technology which uses light sand blasting instead of traditional sand blasting. It is more and more used in the field of ship block construction. In this paper, based on the self circulation sand spraying equipment, the process parameters of light sand blasting are studied. A self circulation sand blasting experiment platform was built to study the surface characteristics of steel plate under different sand blasting pressure and speed. The result show that the surface roughness of steel plate increases with the increase of sand blasting pressure and decreases with the increase of sand blasting speed. The research method and results can provide reference for the implementation of sand sweeping process.