This paper studied the influence of Epson water-based ink vs. UV ink on the quality of the printing line. The Epson water-based ink printer and the UV ink jet printer were used to print the test forms by the two kinds of printing inks in the same resolution settings and on the same paper surface respectively. The PIAS?-II image analysis system was used to measure the vertical line in each printing sample, and the measurement data were saved. The printed line using Epson water-based ink had a uniform width, smooth and clear, in contrast, the printed line using UV ink showed width fluctuations, rough and fuzzy. For prints that call for fine text lines, Epson water-based ink has good performance capacity to meet requirements of high quality.