Objective CT and MRI findings of mediastinal lung cancer were observed, and the diagnostic results were consistent with the pathological diagnosis after operation. . Methods A total of 42 patients diagnosed as mediastinal lung cancer by surgical pathology from May 2015 to May 2018 in our hospital were analyzed retrospectively. All patients accepted CT and MRI examination. The CT and MRI imaging findings and surgical pathological results of all patients were compared, and the consistency between the two diagnostic results and surgical pathological diagnosis was analyzed. Results There were no significant differences in the diagnosis of central lung cancer, peripheral lung cancer, types of lung cancer and disease location among surgical pathology, CT and MRI (P>0.05). The diagnosis results of central/peripheral lung cancer by CT were well consistent with the surgical pathology results (Kappa>0.7). The results of CT diagnosis of squamous cell carcinoma, small cell carcinoma and adenocarcinoma were consistent with surgical pathological results (Kappa>0.4). The results of CT diagnosis of superior lobe of left lung, inferior lobe of left lung, superior lobe of right lung and inferior lobe of right lung were completely consistent with surgical pathology results (Kappa=1.0). The results of MRI diagnosis of central/peripheral lung cancer and small cell carcinoma were well consistent with surgical pathology results (Kappa>0.7). The results of MRI diagnosis of squamous cell carcinoma, adenocarcinoma, superior lobe of left lung, inferior lobe of left lung, superior lobe of right lung and inferior lobe of right lung were completely consistent with the surgical pathology results (Kappa=1.0). Conclusion The diagnostic results of CT and MRI in patients with mediastinal lung cancer are not significantly different from those of pathological examination, and the consistency of the two diagnostic methods is high, but the advantages of MRI diagnosis are obvious. Therefore, reasonable selection can be made according to the actual diagnosis of patients.