The anion UV-curing water soluble prepolymer was synthesized with toluene diisocyanate, dihydroxy compound, dihydroxyalkyl carboxylic acid and polyurethane acrylate. The structure of the prepolymer was characterized by infrared spectroscopy. The effect of different photoinitiators, pigment content, drying technology on the curing speed of ink was also researched. The results shown that the photoinitiator system 819DW and MBF was best matched with the yellow pigment, cyan pigment and black pigment, the optimum content of the pigment was about 10 percent, 10 percent and 11 percent. The photoinitiator system 819DW and 500 was best matched with the magenta pigment, the optimum content of the pigment was about 10 percent．Under the conditions of this experiment, the best pigment content of the yellow, magenta, cyan, black was about 6 percent, 7 percent, 6 percent and 7 percent. The curing rate without pre-drying increased.