Four processing parameters, layer thickness, printing speed, raster angle, and building orientation were investigated in terms of their effects on mechanical properties, surface quality, and microstructure of acrylonitrile-butadiene-styrene (ABS) samples in fused deposition modeling (FDM) by orthogonal experiments. The results show that both the building orientation and the printing layer thickness have a great influence on the mechanical properties of ABS specimens. When the layer thickness is 0.1 mm, samples printed in horizontal direction have the best mechanical performance. The vertical-direction-built parts generally have the worst tensile strength and impact resistance. Moreover, the layer surface quality of the products becomes worse with the increasing of layer thickness and printing speed. The influence of layer thickness on the roughness of FDM samples is still very significant. These researches are of great significance to explore the FDM molding mechanism and optimize processing parameters to meet the performance demands. POLYM. ENG. SCI., 59:120-128, 2019. (c) 2018 Society of Plastics Engineers