The invention discloses an efficient heat-dissipating air cooler which comprises a box. Heat dissipater tube bundles are arranged on the side walls of the box. Spraying devices are arranged on the heat dissipater tube bundles. An oil drainage mechanism is further arranged at the bottom of the box. A draught fan is arranged at the top of the box. The box is a square box. A runner flow guide plate consistent with an air flow field is arranged in the middle of the box. The flow guide plate is laid on a structural member arranged obliquely. Two rows of vertical heat dissipater tube bundles are correspondingly arranged on the two faces opposite to the flow guide plate respectively. The two ends of the flow guide plate are connected with the box of the air cooler. The air cooler is provided with a good air runner structure, the flowing state of air flow in the box of the air cooler is improved, interference of turbulent flow in an air flow channel is reduced, and the cooling effect of the air cooler is improved; lubricating oil in the air cooler can be collected in a centralized manner by utilizing self-gravity of the oil and drained regularly, and the situation that due to accumulation of oil dirt, heat exchange efficiency of the air cooler is reduced greatly can be avoided effectively.