【Objective】 To construct recombinant plasmid pEGFP-N1-apolipoprotein J (apoJ), transfect it into rat bone marrow mesenchymal stem cells (MSCs), and detect its expression in rat bone marrow mesenchymal stem cells in vitro. 【Methods】 Rat bone marrow MSCs were transiently transfected with the recombinant plasmid pEGFP-N1-apoJ and the transfection efficiency of green fluorescent protein (GFP) was determined. Real-time PCR, Western blot and immunocytochemistry analysis were also performed for detection of apoJ expression in rat bone marrow MSCs. 【Results】 Transient transfection efficiency reached 35%. After transfection, the transcription of apoJ was detected in MSCs and the expression of apoJ protein was also verified. 【Conclusions】 Recombinant plasmid pEGFP-N1-apoJ has been successfully constructed, transfected into rat bone marrow MSCs and expressed in rat bone marrow MSCs. This procedure may be helpful for the application of apoJ to gene therapy and provide the experimental basis for the further study of apoJ as a new treatment of cerebral hemorrhage.