Leading slat configurations can affect the flow features of multi-element airfoil, and also have an impact on the distributions of slat noise sources. Based on LES simulations and FW-H integration equation, together with the typical multi-element airfoil 30P-30N model, the flow characteristics and far field noise features are investigated. Through adjustment of slat configurations, the sensitivity of slat noise radiation to slat position parameters is analyzed. The position parameter features are studied by keeping high aerodynamic performances and effectively attenuating slat noise. The study shows, with fixed slat gap and overlap, slightly decreasing slat deflection angle could effectively reduce slat noise without any compromise with aerodynamic performance. On the condition of fixed deflection angle, decreasing gap width, meanwhile increasing overlaps could suppress slat noise to some degree.