Total RNA was isolated from seeds,cowpea cotyledons and matured leaves.The CpTI gene was amplified by PCR after reverse transcription with the conserved sequence acted as primers.PCR products was cloned with pUCm T vector.After sequence,the nucleotides acids homology was 100%,the proteines homology was 91%.The gene expression period difference was appromiatly detected with the highest expression volume at the seeds periods,the cotyledons was second,and the matured leaves was the lowest.