Objective · To induce Mycobacterium tuberculosis into a dormant state by potassium-deficient culture. Methods · The potassium-deficient Sauton medium was used to culture Mycobacterium tuberculosis at logarithmic phase and to induce it into a dormant state. Colony count, resazurin colorimetric assay, and most probable number (MPN) method were used to measure the survival rate and the proportion of dormant Mycobacterium tuberculosis. Transmission electron microscope (TEM) was used to observe the thickening of cell wall. Auramine O-Nile red double fluorescent staining was employed to detect the lipid accumulation and loss of acid fastness. Drug sensitivity test was performed to detect the drug resistance to isoniazide and rifampicin. Results · Mycobacterium tuberculosis turned to spherical, cell wall thickening, experienced lipid accumulation, and loss of acid fastness, and became resistant to antituberculosis drugs after being cultured under potassium-deficient condition for 30 days. Conclusion · Potassium-deficient culture can induce Mycobacterium tuberculosis at logarithmic phase into a dormant state.