A single-layer multi-material surface overlay system based on powder bed additive manufacturing comprises a forming working table board, wherein a forming cylinder is arranged in the middle below the forming working table board; two powder supply cylinders are arranged on two sides of the forming cylinder; two slide rails are configured above the forming working table board through truss mechanisms; guide rods are connected onto two sliders matched with the two slide rails; powder pressing plates are connected with the bottom ends of the guide rods; the two powder pressing plates are controlled by two stepping motors to move leftwards and rightwards respectively and are connected with two control systems respectively. Based on the system, any multi-dimensional and multi-material parts can be rapidly formed, a to-be-adsorbed powder material is adsorbed on the powder pressing plates, the powder material is compacted on the surface of a formed part, and the effect of improving the compactness of the part is realized; the mobile surface overlay system has a high movement speed, realizes accurate control for powder overlaying amount and improves the production efficiency.