Sparganosis is a serious parasitic zoonosis caused mainly by spargana,the plerocercoid larvae of Spirometra erinaceieuropaei (syn.Spirometra erinacei or Spirometra mansoni).S.erinaceieuropaei cysteine protease (SeCP) in sparganum excretory:secretory (ES) proteins recognized by early infection sera was identified by MALDI:TOF/TOF:MS.The aim of this study was to identify afull lengthcDNA sequence of SeCP andto predict the structures and functions of its encoding protein.The conserved domain,physical and chemical parameters,signal peptide,transmembrane domain,epitope,topological structures of the SeCP were predicted by using the NCBI,EMBI,Expasy and other online sites.The Clustal X,BioEdit and MEGA4.1 software were used for multipie sequence alignment and phylogenetic tree construction.The SeCP gene sequence was 1 053bp length with a 1011 bp biggest ORF encoding 336 amino acidsprotein with a complete cathepsin propeptide inhibitor domain and a peptidase_C 1A conserved domain.The predicted molecular weight and isoelectric point of SeCP were 37.87 kDa and 6.47,respectively.The SeCP has a signal peptide site and no transmembrane domain,located outside the membrane.The secondary structure of SeCP contained 8 α:helixes,7 β:strands,and 20 coils.The SeCP had 15 potential antigenic epitopes and 19 HLA:I restricted epitopes.Based on the phylogenetic analysis of SeCP,Spirometra erinaceieuropaei has the closest evolutionary status with Spirometra mansonoides.SeCP was a kind ofproteolytic enzyme with a variety of biological functions and its antigenic epitopes could provide important insights on the diagnostic antigens and target molecular of antiparasitic drugs for sparganosis.