Aldehyde dehydrogenases (ALDHs) represent a protein superfamily of NAD(P)+-dependent enzymes that oxidize a wide range of endogenous and exogenous aliphatic and aromatic aldehydes. The conserved sequence of aldehyde dehydrogenase gene (ALDH) was amplified from Fraxinus velutina by RT-PCR. The results demonstrated that the conserved sequence was 718 bp in length, which was deduced coding 229 amino acids. Homology analysis showed that the deduced amino acids sequence of FvALDH shared 56.9%%-73% identity with aldehyde dehydrogenase from other plants. We examined the expression pattern of the FvALDH gene in leaf treated with NaCl stress for defferent time using semi-quantitative RT-PCR. The results showed that the expression of FvALDH was increased after the first decreased, and then in a steady state with the time went on.