The invention relates to a wind distribution device facilitating discharging of big particle matter and a multi-flow circulating fluidized bed boiler. A horizontal wind distribution plate (28) of the wind distribution device is arranged horizontally. An inclined wind distribution plate (27) inclines downwards from one edge of the horizontal wind distribution plate (28), is in butt joint with the horizontal wind distribution plate (28) and then is arranged in the middle of a hearth. Other edges of the horizontal wind distribution plate (28) and other edges of the inclined wind distribution plate (27) are fixed to the inner ring of the hearth. A plurality of second wind caps (26) are arranged on the horizontal wind distribution plate (28). A plurality of first wind caps (25) capable of directionally outputting wind are arranged on the inclined wind distribution plate (27). A first wind chamber (23) supplies wind to the inclined wind distribution plate (27). A second wind chamber (24) supplies wind to the horizontal wind distribution plate (28). Slag dropping pipes (22) are arranged on the same side of the inclined wind distribution plate (27) and located in the lowest position of an inclined section. The wind distribution device can smoothly discharge the big particle matter disturbing uniform outlet air of the wind distribution plates, and accordingly it can be guaranteed that materials in the hearth are fluidized continuously and uniformly.