Abstract: Objective: To explore the effects of lipopolysaccharide(LPS) on the expression of Toll-like receptor 4(TLR4) and production of intracellular reactive oxygen species(ROS) in peripheral blood mononuclear cells of tuberculosis(TB) patients. Methods: The peripheral blood samples from 13 TB patients and 13 health volunteers were collected, which was dyed with ROS probe DHR123 or anti-TLR4-PE. The expression of TLR4 and production of intracellular ROS in peripheral blood mononuclear cells of TB patients and health volunteers were detected using flow cytometry. The 100 μL anticoagulant blood were cultured in 96-well plates, and divided into group A, group B, group C(6 wells each group) and cultured for 24 h, and treated with 100 ng/mL LPS. The expression of TLR4 and production of intracellular ROS in peripheral blood mononuclear cells were detected by flow cytometry. Results: The positive expression rate of TLR4 in peripheral blood mononuclear cells in TB patients(17.6±3.6)% was significantly lower than that in health volunteer(30.0±2.4)%(P<0.01). The level of ROS in peripheral blood mononuclear cells in TB patients(74.8±11.4) was significantly lower than that in health volunteer(109.6±13.2)(P<0.01). After LPS stimulating for 24 h, the difference of the level of intracellular ROS between group C(182.1±11.3) and group B(127.6±14.1) was statistically significant(P<0.01), and the difference of the expression level of intrcellular TLR4 between group C(62.1±3.3)% and group B(47.6±4.7)% was statistically significant(P<0.01). Conclusions: LPS can increase the TLR4 expression and intracellular ROS production of peripheral blood mononuclear cells in TB patients.