Background Consideration of the huge burden both of tuberculosis (TB) and diabetes mellitus (DM) in China as a major public health issue, research focused on the relationship between DM and TB was needed. Methods An observational study was conducted (2015-2018) in regional representative TB and lung disease hospitals in China. All the adult patients newly diagnosed of pulmonary TB were consecutively recruited in this study. Results A total of 1417 patients newly diagnosed pulmonary TB was recruited in this research, 312 (22.02%) of them had the history of type 2 DM. Majority of patients were with fatigue, loss of weight and mild anaemia in TB-DM group compared with TB-NDM group (58.3% vs 47.5%, p = .001; 8.21 +/- 6.2 vs 5.74 +/- 4.0 kg, p < .001, 88.9% vs 77.6% p = .021). TB-DM patients were with higher the proportion of TB severity score >= 3, compared with TB-NDM patients, but the distributions of drug susceptibility testing (DST) analysis were not significantly different between the two groups of patients. Remarkably, the sign of central shadow of pulmonary lobe distribution and cavity in TB-DM group presented significantly higher rate than it in TB-NDM group. Multivariable logistic regression showed that high uric acid level was an independent risk factor for thick wall cavity in TB-DM patients (OR 2.81, 95% CI 1.24-6.40), haemoptysis (OR 2.43, 95% CI 1.10-5.38) and chest pain (OR 5.22, 95% CI 1.38-19.70) were significantly associated with thick wall cavity. Conclusions The clinical features of TB-DM patients are associated with cavities in CT scan, rather than DST results. It can help us recognition confounding variables, also may influence the treatment strategy and outcomes in TB-DM patients.