The DNA sequence and cDNA sequence of Malus domestica EIN2 were amplified by PCR and RT-PCR,respectively.Bioinformatic analysis of the nucleotide and sequence of EIN2 was performed.The results showed that:(1)The sequences of M.domestica EIN2 amplified by PCR and RT-PCR both are the same,without intron in it.The M.domestica EIN2 was 4 378 bp,containing one opening reading frame of 3 282 bp and coding 1 093 amino acid residues.The molecular weight of M.domestica EIN2 is 118.9 kD,and its theoretical pI is 5.52,and the protein probably is a liposoluble and lyophobic protein.(2)The multiple sequence alignment indicated that the deduced amino acid sequence of M.domestica EIN2 shared 52%,79% and 62% identity with EIN2 of Arabidopsis thaliana (AAD41077.1),Prunus persica (ACY78397.1) and Vitis vinifera (CAN66374.1),respectively.(3)The constructed phylogenetic tree shows that A.thaliana,Thellungiella halophila,Cucumis melo and Populus trichocarpa were clustered together,while P.persica,Petunia hybrida and Solanum lycopersicum were clustered to another group.V.vinifera,M.domestica and Medicago truncatula were clustered in separate groups,respectively.And M.domestica EIN2 is closely related with the homologous genes of P.persica,et al,and the relationships of it with the homologous EIN2 genes in A.thaliana and T.halophila were remote.