Abstract: AIM　To establish models of selective COX2 inhibitors which can help find selective COX2 inhibitors and study their mechanisms of antiinflammatory effects. METHODS　The COX1 model was set up with cultured bovine arterial endothelial cells by detection of 6-keto-PGF_1α in the supernatant of cultured cells. Three different COX2 models were set up with murine peritoneal macrophages. The COX2 activity of tested compounds were evaluated by the detection of PGE2 production from AA in the supernatant of the murine macrophages stimulated with LPS or PMA. RESULTS　Under the stimulation of LPS and PMA, the COX2 activities were markedly induced in a dose dependent manner. Indomethacin and meloxicam significantly inhibited COX1 activities with IC₅₀ of 2.7×10^-10 and 8.7×10^-8 mol.L^-1, respectively. Both of the above also greatly inhibited COX2 activities with IC₅₀ of 5.01×10^-10 and 2.86×10^-8 mol.L^-1, respectively. The ratios of IC₅₀COX1/IC₅₀COX2 were 0.53 and 3.04, respectively. The results showed that indomethacin is a COX1 inhibitor, but meloxicam is a COX2 inhibitor. CONCLUSION　The above three models for evaluation of COX1 and COX2 activities are effective, sensitive, simple, fast and accurate. They can be used for screening selective COX2 inhibitors and also provide a tool for studies of their mechanism of action of the antiinflammatory drugs.