Objective To investigate the histopathological and clinical features of primary mucoepidermoid carcinoma of the lung and the situation of CRTC1/3-MAML2 fusion gene. Methods 17 cases of mucoepidermoid carcinoma of the primary lung in the First Affiliated Hospital of University of Science and Technology of China from 2019 to 2021 were retrospectively analyzed. The clinical information, histopathological morphology, immunohistochemistry and CRTC1/3-MAML2 fusion gene were detected. Results The average age of the patients was 51.3±17.3 years. The proportion of men and women is similar. The tumor size was 3mm to 97mm (mean 27.4±22.6mm). The incidence rate of left and right lungs is similar. 14 cases (82.4%) were low-grade mucoepidermoid carcinoma and 3 cases (17.6%) were high-grade mucoepidermoid carcinoma. The expression rates of CK7 and CK5/6 were 100% in immunohistochemistry. There was no significant correlation between MAML2 gene rearrangement and age, sex, tumor diameter, location and pathological differentiation of patients (P>0.05). Conclusion The frequency of CRTC1/3-MAML2 fusion gene rearrangement is high in MEC, so MAML2 gene rearrangement can be one of the molecular diagnostic indicators of PMEC.