The invention discloses an energy-saving full-automatic four-axle horizontal tapping machine, comprising a rack, a discharging device, an engine body protective cover, an arrangement device, a coolant oil circulating device, a control device, a pneumatic material pushing device, a tapping device, a material guiding device, and feeding devices. Through adding the coolant oil circulating device on a conventional four-axle horizontal tapping machine, the machine greatly reduces production cost of a nut tapping production process. Four oil distribution pipes of the machine are in a parallel structure, so phenomenon that flow of the four oil distribution pipes is not uniform is prevented. Through adding two feeding devices beside a conventional four-axle horizontal tapping machine, feeding operation of the conventional four-axle horizontal tapping machine is more convenient and easy. Through directly fixing the arrangement device on an arrangement device fixing boss, the arrangement device is fixed more firmly, and material feeding and guiding of the arrangement device are more accurate.