Abstract： Objective: To investigate the clinicopathological features and prognostic factors of invasive mucinous adenocarcinoma of the lung(IMA) . Methods: From January 2015 to December 2019, 106 patients were identified as having IMA accepted radical resection and enrolled in the retrospective study. Their clinicopathological features were analysed and we conducted a survival analysis with statistical software. Results：14 patients showed pneumonia on preoperative CT images. All patients received radical surgery, and 50 patients received postoperative adjuvant therapy. Univariate survival analysis showed that pneumonia type, T stage and N stage and whether adjuvant treatment were the factors affecting the overall survival rate of IMA patients (P < 0.05). In addition, the expression of pneumonia, T stage, N stage, operation method and whether adjuvant treatment were related to the disease-free survival rate (P < 0.05). Multivariate survival analysis of Cox risk assessment model showed that pneumonia and lymph node metastasis were independent risk factors affecting the overall survival rate and disease-free survival rate of IMA patients (P < 0.05). Conclusion: The manifestation of pneumonia and lymph node metastasis are associated with the poor prognosis of IMA.