Based on hybrid-solving method, by dividing the sound field computational domain into four different parts, the influence of different parts of the 2-D multiple elements airfoil on far field sound pressure level was investigated and the sound field mapping and far field directivity were presented. It was found that the noise contribution of slat and main airfoil on far field is far less than that of flap trailing edge, which dominates for overall sound pressure level and should be paid priority attention.