A calmodulin gene named MaCAM was obtained by RACE technology based on a fragment from banana’s root cDNA library.The full length of this gene was 845 bp and encoded 149 amino acids.The result of bioinformatics showed that this protein is a stable protein with two conserved function domains——EFh,which pI is 4.12.Compared with other plant calmodulin genes,the identity of MaCAM was more than 90%.Amino acids identity analysis indicated that MaCAM had 99.33%,96.71%,98.00%,98.66% similarity compared with Oryza sativa var.japonica,Elaeis guineensis,Daucus carota and Saccharum officinarum,respectively.This gene had the most familiar genetic relationship with that of S.officinarum.RTPCR analysis showed that MaCAM was constitutively expressed in roots,stems,leaves,flowers and fruits.The expression level was the highest in root,flower followed in,and was the lowest in leaves.