Objective:To investigate the risk factors of diabetes mellitus complicated by pulmonary tuberculosis.Methods:The clinical data of 83 patients with diabetes mellitus complicated by pulmonary tuberculosis who received treatment in Taiyuan Fourth People's Hospital from March 2020 to March 2022 were collected. These patients were divided into sensitive group ( n = 45) and resistant group ( n = 38 ) according to the results of drug sensitivity test. Univariate and multivariate non-conditional logistic regression was performed to analyze the influential factors of drug resistance. Results:Univariate logistic regression results revealed that there were significant differences in blood CD4 +T lymphocyte count ( χ2 = 11.73, P = 0.001) and diabetic complications ( χ2 = 4.94, P = 0.026). Multivariate non-conditional logistic regression analysis was performed taking whether blood CD4 +T lymphocyte count was lower than the average level and whether patients with diabetes mellitus had complications as independent variables, and taking whether drug resistance was a dependent variable. The results showed that the OR (95% CI) value of the decreased blood CD4 +T lymphocyte count was 4.909 (1.926-12.514). It is a risk factor for drug resistance of diabetes mellitus complicated by pulmonary tuberculosis. Conclusion:The decrease of blood CD4 +T lymphocyte count is a risk factor of drug resistance in diabetes mellitus complicated by pulmonary tuberculosis, and it should be intervened early in the clinic.