Objective To construct an RNAi lentiviral vector targeting rat CD86 gene and detect its effect of gene silencing in dendritic cells. Methods The effective sequence of siRNA targeting rat CD86 gene was confirmed in our previous work. DNA oligo containing short hairpin frame was synthesized and re-annealed, and then cloned into pGCL-GFP lentivind expression vector. PCR and sequencing analysis were made for verifying the positive clones. The virus packaging plasmids were transfected into 293T cells to har-vest shRNA lentivirus. After infection in dendritic cells, real-time PCR and Western blot were performed to determine the expression level of CD86 at mRNA and protein of NC( negative control virus). Results PCR and sequencing analysis revealed that shRNA plasmid was correctly constructed. Virus with a titer of 2×108 TU/ml was successfully packaged. CD86 expression in dendritic cells can be knockdown at both mRNA and protein level by virus infection as characterized by 90.6% decrease of mRNA and significant inhibition of protein compared with NC. Conclusion The recombinant lentiviral shRNA expressing vector targeting rat CD86 gene has been successfully constructed and packaged. CD86 mRNA and protein can be effectively down-regulated in dendritic cells.