The utility model relates to a boiler field discloses a circulating fluidized bed boiler and air distribution plate thereof, and this air distribution plate includes air distribution plate body (1), passes this air distribution plate body (1) and extends and have a plurality of tuber pipes (2) in cavity wind channel (2a) and install in each hood (3) on tuber pipe (2), be equipped with on hood (3) with the trompil (3a) of the wind channel (2a) of tuber pipe (2) intercommunication, wherein, part at least tuber pipe (2) throttle steel (4) on the inner wall that is connected to this wind channel (2a) have in the wind channel (2a) to can offset to passing through the air current in wind channel (2a) produces throttling action. The utility model discloses can be according to the airflow direction of different zone and select the to throttle biasing position of steel (4) to make entering furnace's air current comparatively even, improve the fluidization effect of regional area. Throttle steel (4) only is connected to wind channel (2a's) inner wall in one side, implement relatively more easily.