The invention relates to a dimidiate four colour offset press of printing industry, including a paper transport mechanism, four printing units, a paper transfer roller, a paper accept mechanism, a machine frame, the four printing units are respectively provided on the machine frame, the paper transport mechanism uses non-round gear sets to adjust feeding speed of the paper; the printing units are composed of a water ink system, a plate cylinder, a rubber blanket cylinder, an impression cylinder, a follow-up mechanism, a clutch press mechanism; the water ink system is a mechanism with temperature control and feedback device; the plate cylinder is a forme mechanism with a diagonal regulation mechanism, a circumference direction regulation mechanism, an axial direction regulation mechanism, a quick lerrerpress makeready device; because the paper transport mechanism regulates speed by engaging the two sets of non-round gear, the paper transport mechanism is provided with a position detecting feedback device, a changing ink stick is designed to structural form of regulating temperature control, a forme refulating device is provided on the plate cylinder, thereby the printing quality is good and the automation control degree is high. |