Abstract: The full length cDNA sequence of Fasciola gigantica cathepsin L gene was isolated from cDNA library using the method which combined the touchdown and gradient PCR. The library vector and gene specific primer had been designed for performing the touchdown and gradient PCR.The products of PCR were cloned into pMD18-T vector and then sequenced. The bioinformatic analysis was used to predict the ORF, amino acid sequence, amino acid homology alignment,the secondary and tertiary domain, and so on. The extended sequence is composed of 990 base pairs coding 330 amino acids which MW and PI are 36 771.2 u and 5.44, respectively.The secondary structure prediction showed that the alpha helix,bata sheet and coil are 17.3%,27.0% and 55.8%, respectively.Two transmembrane areas and two hydropathicity profiles were found but without significant signal peptide and glycosylation sites. Results of amino acid alignment against SWISS-Port database showed that the sequence belongs to the cysteine family.And the three diamensions picture has been gained by the way of Mock construction of molecular confirmation which showed the 49% homology with the cathepsin K gene.