Abstract: A warpage mathematical model was established for warpage defects in the FDM 3D printing process, and the effect and variation trend of layer thickness, printing temperature, plate temperature and product thickness on the warpage of the printed parts were analyzed by an orthogonal experiment. The experimental results were verified by the mathematical model. The results indicated that there was a significant effect of layer thickness on the warpage and the printing temperature also affected the warpage considerably. However, the effects of plate temperature and wall thickness of the parts were not remarkable. The printing precision was improved significantly by 44.4 % with optimizing the FDM process parameters.