The work aims to study the role of each performance of paper and printing ink (among the factors that affect the quality of offset image) in the saturation, gloss and abrasion resistance, etc. 2 kinds of inks were used for the offset printing of 3 types of kraft paper. Then, partial least square (PLS) was used to analyze the effects of smoothness, gloss, surface pore and ink viscosity of the paper and the particle size, etc. on the color saturation and gloss of the image and the friction resistance of ink layer. The results showed that the paper gloss and surface average aperture had significant impact on the offset image quality, had small impact on the smoothness and relative aperture depth of the paper, and had the least impact on the performances of the ink. The correlation between saturation, gloss and friction resistance tion change) of the offset image and smoothness, pore relative depth and gloss of the paper was large; while the correlation with other influence factors was relatively small. In conclusion, in the process of offset printing, the improvement of gloss and smoothness of the paper and the proper adjustment to surface average aperture and pore relative depth of the paper can improve the image quality largely.