Following with the development and cooperation between digital printing techniques and digital distribution in publishing industry, more and more books will be printed by digital printing equipments, and then the storage stability became one of the focuses in digital printing research field. This study is to investigate the storage resistance property of inkjet presswork. In this paper, based on analyses about factors which influence photoaging phenomenon, a mathematic model which can separate the influence factors and an analytical method were proposed. Then, the experiment under absolutely natural lighting conditions was carried out, and the density decrease, which indicated the color change phenomenon after photoaging, were measured by an X-rite Spectroeye instrument. Through curve-fitting method, an empirical model was derived to demonstrate the rule of ink photoaging fading. Finally, the photoaging property of substrate and ink was analyzed, and the photoaging properties of the inkjet print were generalized. The research methodology and the fading model are of significant reference to the following research about photoaging phenomenon.