G protein coupled receptor 84(GPR84) is medium-chain fatty acid-sensing receptor(C9～C14). It plays an important role in metabolism of fatty acid and immune response, and it's also deeply involved in inflammatory immune diseases such as multiple sclerosis and endotoxemia. It may provide an effective method to treat these diseases by finding GPR84 ligands. It's important to construct a cell line stably expressing human GPR84 for screening its ligands and researching diseases. In this research, we transfected plasmids encoding GPR84 and Gα16 proteins into HEK293 cells. After selection with antibiotics, we picked out monoclones which stably expresses GPR84 to form cell lines. The permanent expression of exogenous GPR84 proteins in HEK293 cells was detected by RT-PCR, immunofluorescence staining, calcium mobilization and cAMP assay. Western blot and FACS were conducted to examine the activity of GPR84. Above all the results demonstrate that GPR84 receptor has excellent biology activity. Based on cell lines stably expressing GPR84, we conducted high-throughput assay for the screening of GPR84 ligands and found new GPR84 antagonists. We can further research on the biological functions of GPR84 and immune diseases targeted GPR84 with these antagonists.