In order to obtain a full-length expression plasmid for the p53 inhibitor protein, iASPP, fractional amplification was used to clone its full-length coding sequence (CDS) region. The amplified PCR product was then digested and inserted into the pMD19-T simple vector and subcloned into the pCDNA3.1(+) vector. A recombinant eukaryotic expression vector containing the complete CDS region of iASPP was successfully constructed. pcDNA3.1(+)/iASPP was able to express iASPP protein in an in vitro translation system and in cells. Its biological activity was verified using Western blotting, immunoprecipitation and cell apoptosis analysis. This successful preparation of a full-length iASPP expression plasmid lays the foundations for further studies on the function of iASPP.