Based on the surface sizing process in the papermaking field and simple inkjet printing technology, a hydrophilic microfluidic channel was constructed on the surface of the paper. Taking the wettability of the paper surface and the diffusion property of the liquid in the channel as the evaluation criteria, the paper studied the effect of surface sizing agent ratio and calendering treatment on the diffusion behavior of fluid in the microfluidic channel. First, the cellulose paper was hydrophobically modified by using a surface sizing agent with a ratio of 7∶3 (msurface sizing starch/mAKD), and then the modified paper was calendered at the pressure of 2MPa with a speed of 3.5m/min. The results demonstrated that constructed microfluidic channel exhibited an excellent liquid limiting performance. In these hydrophilic channels, the liquid can achieve a complete directional diffusion, and the z-direction liquid diffusion problem was also solved. Finally, the paper-based chip was further applied for the quantitative detection of nitrite, which shows that there is a good correlation between the solution mass concentration and the color difference value of the chip surface. The corresponding curve fitting equation is y=1.799＋8.745x0.453  and the correlation coefficient is 0.9935.