Abstract: object: To analyze the antituberculosis action of baicalin on Mycobacterium tuberculosis by Antimicrobial Susceptibility Testing in vitro. methods: Detecting Bacteriostatic Action of baicalin on Mycobacterium tuberculosis by absolute consistence method of Lowenstein-Jensen. results: MIC minimum of baicalin on 37 strains Mycobacterium tuberculosis was 1.5 g/L, MIC maximum was ＞48 g/L.MIC90 was 12 g/L, MIC75 and MIC50 was 6g/L.The number of drug sensitive Mycobacterium tuberculosis was most in 6 g/L MIC, and decrease progressively with MIC value reduce or increase. there was not relevance between the strain number of INH mild drug resistance Mycobacterium tuberculosis and the MIC value. The number of EMB mild resistance strain was increase progressively with MIC value increase（MIC 3-9g /L）. The number of RFP mild resistance strain was decrease progressively with MIC reduce（MIC 2-8 g/L）.conclusion: there is antituberculosis action of baicalin on Mycobacterium tuberculosis.

Key words: baicalin, Mycobacterium tuberculosis, Bacteriostatic Action