Abstract: In order to get the fusion protein which has the bioactivities of both porcine interleukin-2 (pIL-2) and porcine interleukin-6 (pIL-6) and explore the feasibility of the fusion protein as immunoadjuvant, the mature peptide genes of pIL-2 and pIL-6 were linked by a fragment which consisted of hydrophilic and low charge base pairs. Then they were subcloned to pBV220 for prokaryotic expression. The recombinant plasmid was transformed into E. coli DH5α, E. coli BL21(DE3) and E. coli Rosetta(DE3) and then induced at 42 ℃. SDS-PAGE analysis showed that the target protein pIL-6-2 was about 36.7 kDa in molecular weight which existed in inclusion bodies. The biological activity of the expressed protein was authenticated by MTT after being purified and refolded. The results showed that the effects of different concentrations of pIL-6-2 are significantly diverse in inducing the proliferation of lymphoblast cells from the spleen of mice. The concentration of 0.1 μg·mL^-1 pIL-6-2 exhibited the best effect. This study laid foundation for the application of this protein as a novel efficient immune reagent.