To investigate the correlation between computed tomography (CT) features and glycosylated hemoglobin (HbAlc) levels in patients with type 2 diabetes mellitus (T2DM) complicated with primary pulmonary tuberculosis (PTB). One hundred and eighty untreated PTB patients complicated with T2DM were selected. Based on the HbAlc level, the patients were divided into three groups: HbAlc level <7% (Group I: 32 patients), 7%-9% (Group II: 48 patients), and >9% (Group III: 100 patients). The changes of CT manifestations and HbAlc were analyzed after TB and T2DM treatment. In the three groups, the detection rate of large segmented leafy shadow was 50%, 56.2%, and 87%; the air bronchogram sign detection rate was 40.6%, 47.9%, and 77%; the discovery rate of mouth-eaten cavity was 31.2%, 45.8%, and 65%; thick wall cavity detection rate was 25%, 31.2%, and 52%; the rate of multiple cavities was 34.3%, 50%, and 73%; and bronchial TB was found in 33.3%, 21.8%, and 46%, respectively. The detection rates of lesions in Group III were significantly higher than in Group II and Group I (p<0.05), and this increase was significant (p<0.05). After treatment, the HbAlc level reached control target (<7%) among all three groups and CT absorption improvement rates were 100%, 72.9%, and 56% respectively. The therapeutic efficacy of group I was better than group II (p<0.01), and the treatment efficacy of group II was better than group III (p<0.05). CT manifestations of T2DM complicated with PTB were closely related to HbAlc level. The effect is better when HbAlc level <7%. HbAlc level effectively reflects the severity and therapeutic effect to a certain extent. CT scan can provide some important information for clinical imaging. The above two examinations can guide clinicians to formulate the appropriate diagnosis and treatment in a timely manner.