The invention relates to a finned tube for a falling film evaporator, which comprises a tube body with a channel therein and fins arranged on the outer surface of the tube body. A rough layer formed through sand blasting is arranged on the outer surface of the finned tube. Therefore, when the refrigerant is injected to the rough layer of the finned tube, since the rough layer has high flow resistance and high adhesion to the refrigerant, the refrigerant can form a liquid film on the rough layer for heat exchange with liquid flowing in the tube, thereby enlarging the area for evaporation and heat exchange. Moreover, the rough surface can disturb the fluid boundary layer, thereby improving the efficiency of falling film evaporation, enhancing the boiling along with the falling film evaporation, increasing generated bubbles, and further improving the heat exchange efficiency of the heat exchange tube.