CB2R antagonist 3 is a selective antagonist of cannabinoid type 2 receptor (CB2R). CB2R antagonist 3 has high affinity for human CB2R and specific selectivity for CB1R. CB2R antagonist 3 can be combined with CB65 , the activator of CB2R. CB2R antagonist 3 effectively up-regulates the expression of anti-inflammatory cytokines and down-regulates the expression of pro-inflammatory cytokines.