With the development and advancement, digital printing has become a leading technology. Liquid electronic ink is a kind of charged liquid ink, which is the core of HP Indigo different from others. The particle of ink is small with good color reproduction, stable physical property and the printed material widely. It is the only ink of digital printing to reproduce 95% of Pantone colors. The purpose of the experiment is getting the rheological curves in a different proportion of the original electronic ink mixed with the image oil. The impact of the proportion of image oil to the viscosity and surface tension will be got to discuss the function of the oil in printing. We mixed the ink and oil at the proportion of 1:1, 2:1, 3:1, 1:2, 1:3, and tested the steady-state rheology and dynamic rheology. The results show that with the mixture proportion changed, the viscosity change.