Numerical study was done to assess the performance of trailing edge high lift devices with downward deflection of spoiler.By analyzing coupling motions of downward deflection of spoiler and trailing edge flap with simple hinges, specific mechanisms were put forward.Moreover,the wing camber was increased with downward deflection of spoiler,thus increasing cruise lift-drag ratio and improving economic efficiency. With CFD numerical analysis and iSIGHT optimization platform,the low speed takeoff/landing and cruise performance of the large aircraft with downward deflection of spoiler using simple hinges were analyzed and assessed.