Geometric structures of Aun Sc3 (n=1—7) clusters are optimized by using the generalized gradient approximation (GGA) density functional theory. Energy, vibrational frequency and electronic properties have been calculated. The 3D structure of AunSc appears earlier than that of Aun. The triangle bipyramid structure of Au2Sc3 is a building block for larger AunSc3 of n≤7. Furthermore, the investigation on the second-order difference shows that the clusters with even Au atoms have enhanced stabilities, which may be due to the electron shell effects.