ObjectiveTo observe the expression of Cox2 and Ki67 protein in mucoepidermoid carcinoma (MEC) and normal salivary gland(NSG), so as to search for biomarkers for evaluation of MEC prognosis. Methods The expression of Cox2 and Ki67 protein was examined by PV6001 staining in 11 NSG and 34 MEC samples, and the experimental data were statistically analyzed by SPSS 16.0 software. ResultsThe expressions of Cox2 were significantly different between MEC and NSG samples (P<0.01).Cox2 expressions were also significantly different between MEC samples with different differentiation, metastasis and recurrent statuses(P<0.05,P<0.01), and were similar between those with different sexes, ages, or ethnicities(P＞0.05).The expressions of Ki67 were significantly different between MEC and NSG samples (P<0.01). Ki67 expressions were also significantly different between MEC samples of high and moderatedifferentiation degrees with lowdifferentiation degrees, and samples with different recurrence, and metastasis statuses and sites(P<0.05,P<0.01), and were similar between the highdifferentiation and middledifferentiation samples, and samples with different sexes, ages, and ethnicities. Cox2 expression was positively correlated with Ki67 expression in MEC samples (rs=0.788, P<0.01). ConclusionCox2 and Ki67 expressions in MEC are associated with the pathological types of MEC, and they may participate in the development and progression of MEC. High expression of both is associated with local infiltration and distant metastasis.Codetection of Cox2 and Ki67 is helpful for predication of MEC prognosis.