Objective Screening the immune polypeptide sequence of toxoplasma (Tg) CDPK5 gene ,which were synthesized and then immunized the New Zealand white rabbit to prepare antiserum ,and identification its function .Methods Bioinformatics a‐nalysis was used to determine the immune peptide of Tg CDPK5 sequence ,which were artificially synthesized to immune white rab‐bit to prepare antiserum .The titers of antibodies were determined by ELISA and the polyclonal antibodies were verified with CD‐KP5 antigen by Western blot .The sub‐cellular localization of Tg CDPK 5 were obtained by immunofluorescence assay .Results 17 bp peptide sequence from the Tg CDPK5 N‐terminal were chosen as immune polypeptide by bioinformatics analysis .Synthetic pep‐tide were used to immune rabbit to obtain polyclonal antiserum .The result showed that the titer of the obtained ployantibody were 1∶640 000 ;Western blot demonstrated that the antiserum could specifically recognize Tg CDPK 5(75 .4 × 103 );Immunofluores‐cence assay revealed this antibody could specifically recognize the endogenous Tg CDPK 5 of Toxoplasma gondii .Conclusion Ac‐cording to the analysis of Tg CDPK5 sequence information ,this study successful obtained Tg CDPK5 polyclonal antibody .