Abstract: Angiotensin converting enzyme(ACE) in Danio rerio was predicted and analyzed by using bioinformatic tools.The results showed that there were two ACE genes,i.e.,wu:fb81h03 and danio:ace2,encoding 1324 and 782 amino acids,respectively,in Danio rerio genome.Wu:fb81h03 is an acidic,water-soluble,unstable mitochondria trans-membrane protein containing no signal peptide.On the other hand,danio:ace2 is an acidic,water-soluble,stable and contains a signal peptide.Both of them include a conserved domain,Pfam Peptidase_M2,indicating that they belong to M2 family proteins.Through the analysis of ESTs,these 2 genes were found to express differentially in different tissues and growth stages.Homology BLAST and phylogenetic analysis indicated that D.rerio ACE was close to ACEs from lower vertebrates(e.g.,Gallus gallus and Xenopus(Silurana) tropicalis) and higher vertebrates(e.g.,human and mouse).The homological percentage was more than 60%,suggesting that the ACE was conserved through the evolution process.