The equilibrium geometric structures, stabilities, and electronic properties of bimetallic AunCs (n = 1-10) and pure gold Au-n (n <= 11) clusters have been systematically investigated by using density functional theory with meta-generalized gradient approximation. The optimized geometries show that one Au atom capped on Aun-1 Cs structures and Cs I atom capped Au-n structures for different sized Au Cs (n = 1-10) clusters are two dominant growth patterns. Theoretical calculated results indicate that the most stable isomers have three-dimensional structures at n = 4 and 6-10. Averaged atomic binding energies, fragmentation energies, and second-order difference of energies exhibit a pronounced even-odd alternations phenomenon. The same even-odd alternations are found in the highest occupied-lowest unoccupied molecular orbital gaps, vertical ionization potential, vertical electron affinity, and hardnesses. In addition, it is found that the charge in corresponding AunCs clusters transfers from the Cs atom to the Au-n host in the range of 0.851-1.036 electrons.