The invention aims to provide an energy-saving speed reducer for an efficient escalator. The energy-saving speed reducer comprises a speed reducer casing, a speed reducer shaft, oil sealing sheets, aleft oil inlet channel, a lubricating oil accommodating cavity, a bearing, a transmission gear, a gear shaft, a first input gear, a gear transmission device, a gear connecting shaft, a second input gear, an input shaft, a first-stage transmission shaft, an output gear, a right oil inlet channel, a cooling cavity, a condensation pipe, a condenser, exhaust vents, a gas collecting hood and an outputshaft, and the energy-saving speed reducer is characterized in that the speed reducer shaft is mounted on the speed reducer casing; the cooling cavity is formed in the speed reducer casing; the lubricating oil accommodating cavity is formed in the speed reducer casing; the speed reducer shaft is arranged in the lubricating oil accommodating cavity; the oil sealing sheets are arranged at the upperend of the lubricating oil accommodating cavity and fixedly connected with the lubricating oil accommodating cavity. The two oil sealing sheets are arranged at the upper end of the lubricating oil accommodating cavity and fixedly connected with the lubricating oil accommodating cavity, and the function of preventing oil leakage is realized.