The invention discloses an efficient energy-saving transmission case. The efficient energy-saving transmission case comprises a shell and a transmission mechanism; the transmission mechanism is provided with a drive gear, a transition gear and a driven gear which sequentially mesh with one another and adopt bevel gears; the drive gear is provided with a drive shaft connected with an engine, the driven gear is provided with a driven shaft connected with a hydraulic pump, and the transition gear is provided with a transition gear shaft and two conical roller bearings which are symmetrically arranged; each conical roller bearing is provided with a conical annular rolling space, each rolling space is provided with a conical small-head end with the small radius and a conical large-head end withthe large radius, the two conical small-head ends of the two conical roller bearings are arranged inwards and adjacently, and the two conical large-head ends are arranged outwards; and the drive shaft, the transition gear shaft and the driven shaft are arranged in parallel, and the axis of the drive shaft, the axis of the transition gear shaft and the axis of the driven shaft are arranged in a triangular vertex mode. According to the efficient energy-saving transmission case, the three gears cooperate with speed ratio adjustment, the hydraulic pump fully absorbs the torque of the engine, andhigh efficiency and energy conversation are achieved; the bearing capacity of the conical roller bearings is high, and therefore the service life of the transition gear can be prolonged; and comparedwith the existing installing structure that the three gears mesh with one another side by side, the size of the transmission case can be decreased.