Abstract: Objective To genotype clinic Mycobacterium tuberculosis isolates with multilocus variable number tandem repeat analysis(MLVA)and to provide scientific basis for prevention and control of tuberculosis.Methods Totally 15 variable number tandem repeats(VNTR)loci were analyzed with PCR and agarose gel electrophoresis.The gene diversity was analyzed with BioNumerics 3.0 software.Results A total of 127 different allele profiles(including 90 unique patterns)were identified by 15 VNTR loci for all 215 isolates of 7 clusters.For all isolates 74.88%(161/215)were dominant in Gansu province.Univariate analysis showed that the clustered strains were not significantly associated with the resistance to all of four drugs(rifampin,isonicotinyl hydrazide,ethambutol,and streptomycin),patient's gender,age,regular on irregular therapy,and newcases or relapses(P > 0.05 for all),while significantly associated with antituberculosis therapy history(P >0.05).Conclusion The strains of Mycobacterium tuberculosis isolated in Gansu province present definitely gene diversity.