To construct recombinant eukaryotic expression plasmid vector of human IL-34 gene, and to study the effects of IL-34 expressed by human bone marrow-derived mesenchymal stem cells (hBM-MSCs) on THP-1 cells. Full-length IL-34 encoding sequence was amplified by PCR. And this fragment was cloned into the plasmid pIRES2-EGFP. Western blotting and ELISA were used to analyze the expression of IL-34 in hBM-MSCs. THP-1 cells were cultured with hBM-MSCs medium containing IL-34 protein. Real-time PCR detected the effects of IL-34 on the expression of IL-10 and TNFα in THP-1 cells. Restrictive enzyme analysis and sequencing demonstrated that IL-34 eukaryotic expression vector was successfully constructed. IL-34 protein expressed by hBM-MSCs could promote IL-10 and TNFα expression in THP-1 cells. Those results show that IL-34 expressed by hBM-MSCs has regulating effect on THP-1 cells.