the inking system is one of the important components of an offset printing machine and an inking system with good performances is the necessary condition for high quality printing. In this paper, the Reynolds equation for ink transfer was deducted on the basis of the elastohydrodynamic lubrication theory and the relation model between parameters of the roller, speed, pressure and ink thickness in gap of rollers was established by applying the Hertz contact theory, so as to obtain the minimum film thickness equation in gaps of rollers. The influences of roller speed, pressure and size on ink thickness in gaps of rollers were analyzed. In addition, the ink transfer model was modified under the condition of considering retention of ink in gaps of rollers by using Roland700 as the object and the influences of printing speed on inking characteristics were analyzed by applying the method of computer simulation. The results showed that the longer was the inking stabilization time of the system was, the higher the printing speed was.