The invention discloses a three-shaft three-door energy-saving air lock with single-cam transmission. The three-shaft three-door energy-saving air lock is provided with a shell body, wherein a charge port is formed above the shell body, and a discharge port is formed below the shell body; a partition is arranged at a middle part in a cavity of the shell body and divides the inner cavity of the shell body into a front discharge channel and a rear discharge channel; a lower blade is installed at the centre of a lower part of each discharge channel through a lower rotary shaft; and one end of each of the two lower rotary shafts is connected with a transmission mechanism and a drive motor. The three-shaft three-door energy-saving air lock is characterized in that an upper rotary shaft is installed at the middle part of the shell body and at a top end of the partition, a lower end of one upper blade is in assembling connection with the upper rotary shaft, an upper end of the upper blade realizes closing or opening for the front discharge channel and the rear discharge channel through left-right swinging, and one end of the upper rotary shaft is connected with the transmission mechanism and the drive motor; and the upper rotary shaft and the lower rotary shafts share one cam transmission mechanism. The three-shaft three-door energy-saving air lock disclosed by the invention is simplified in structure and increased in capacity, direct impact wear of materials for the upper blade is reduced, the life of the product is prolonged, and stable and reliable running is achieved; and the three-shaft three-door energy-saving air lock is mainly applied to a pneumatic transmission as well as ventilation and dust removal system in industrial production.