Calmodulin（CaM） plays an important regulatory role in a variety of in vivo Ca2+-dependent cell functions and enzyme systems. It was the first time to clone the calmodulin gene from Phenacoccus solenopsis Tinsley. The full-length of open reading frame (ORF) is 447 bp, encoding 148 amino acid residues. PsCaM gene was constituted by three introns and four exons. The intron lengths were 73,81，72 bp; The lengths of the 4 separated exons were 33,133,183，98 bp. Functional domain analysis showed that the protein got two EF-hand domains, with 13 Ca2+ binding sites. The theoretical protein isoelectric point is 6.21. It was stable protein, with no transmembrane region. The three-dimensional structure of its protein was obtained by homology modeling. Multiple sequence comparison revealed that the gene is relatively conservative. The research was the basis for further study of the functional mechanisms of calmodulin genes. 