The work aims to study the high-quality 3D printed color appearance obtained based on UV ink-jet system. Based on the FDM method, the right angle ladder models with different printing thicknesses and inclination angles were designed and processed. The model surface was subject to the standard coloring of color lump by UV inkjet platform. The mechanism of influence of the staircase effect on the inkjet coloring coating and the repair effect of the inkjet on the 3D printing were discussed. The model surface image was subject to the microscopic observation and the chromatic value of the color lump was measured. Based on the comparative analysis, the uncolored stripes caused by the printing thickness and inclination angle were the main factors that affected the inkjet coloring effect on the 3D printing model surface. The staircase effect can be repaired by UV white ink coating to obtain high-quality 3D printed color appearance.