Abstract: Based on the analysis of process parameters such as printing speed, layer thickness and infill density, through the formula of equal volume ratio, the theoretical relationship between the layer thickness and the width of extruded wire was obtained at different printing speeds. Then, according to the wire lap model, theoretical analysis of modeling accuracy in horizontal direction was performed. The theoretical analysis was verified by the designed experiment which configured three process parameters: printing speed of 30, 40, 50 mm/s, layer thickness of 0.1, 0.2, 0.3 mm and filling density of 90%. The experimental results show that the optimum modeling accuracy in horizontal direction is obtained on the basis of ensuring the modeling accuracy in vertical direction when the layer thickness is 0.2 mm, the printing speed is 30~40 mm/s, and the filling density is 90%.