The geometrical structure and electronic properties of the Al_nCl(n=2~14) clusters have been investigated by using the density functional theory (DFT) at B3LYP 6-311G+(d) level, based on the crystal structure analysis by particle swarm optimization(CALYPSO). The binding energies, energy-gaps, second-order energy difference， fragmentation energy of the clusters and the properties of infrared and Raman spectrum are also discussed. The calculated results indicate that: the most stable structures of Al_nCl(n=2~14) clusters develop from planar to threedimensional structure; the Al_n-1Cl structure capped with one Cl atom is the dominant growth behavior for different sized Al_nCl(n=2~14) clusters; Al₇Cl is the magic cluster. The Al_nCl(n=2~14) clusters exhibit stronger infrared intensity at the higher frequency band. On the contrary, Al_nCl(n=2~14) clusters have more Raman vibrational peaks and it exhibits stronger Raman activity at the lower frequency band.