The density functional method with relativistic effective core potential has been employed to investigate systematically the geometrical structures, relative stabilities, growth-pattern behaviors, and electronic properties of small bimetallic M2Aun (M = Ag, Cu; n = 1-10) and pure gold Au-n (n <= 12) clusters. The optimized geometries reveal that M-2 substituted Aun+2 clusters and one Au atom capped M2Aun-1 structures are dominant growth patterns of the stable alloyed M2Aun clusters. The calculated averaged atomic binding energies, fragmentation energies, and the second-order difference of energies as a function of the cluster size exhibit a pronounced even odd alternation phenomenon. The analytic results exhibit that the planar structure Ag2Au4 and Cu2Au2 isomers are the most stable geometries of Ag2Aun and Cu2Aun clusters, respectively. In addition, the HOMO-LUMO gaps, charge transfers, chemical hardnesses and polarizabilities have been analyzed and compared further.