Abstract: In order to explore the factors affecting the forming quality of powder-bonded 3D printing process, this paper uses the sand bed laying stage of sand mold printing to analyze the law between the roll radius and the sand laying quality based on solid mechanics, and obtains the change of the sand laying quality with the roller radius trend. Through the derived formula, the value range of the roller radius under the specified sand bed scale is given. The discrete element simulation software EDEM is used to establish the numerical simulation model of the sand laying stage, and the quality measurement of the sand bed after sand laying with rollers of different sizes is completed on the constructed sand bed. The results are in good agreement with the calculation results of the proposed theoretical formula, and the validity of the theoretical formula is verified by simulation.