According to World Health Qrganization (WHO)’s global tuberculosis control report, up to one-third of the global population is estimated to carry latent Mycobacterium tuberculosis （M.tb）infection. Although following M.tb infection, only 5 to 10% of immunocompetent individuals develop active tuberculosis （TB）, this disease remains a major health problem particularly in low-income developing countries, which currently causes over 2 million deaths annually and is predicted to be among the 10 leading causes of disease burden even in the year 2020. India, China, Pakistan and Indonesia together account for 50% of the global TB epidemic. In sub-Sahara Africa, because of high HIV prevalence the TB incidence reaches 290 per 100 000 which is a hundred times of developed countries. Molecular epidemiology studies have shown that diverse strains of different genotypes were prevalence in different regions such as the predominance of W-Beijing family, one of the most successful M.tb families, in countries of East Asia. The notion that some strains of a single genotype, such as the W-Beijing genotype, are more virulent than others is supported by results obtained with animal and cellular models. The inhibition of the host immune response by mycobacterial strains of the W-Beijing family has recently been confirmed in vivo. This review discusses the phylogenetic studies that have been made in discovering how certain M.tb has achieved its virulence as a successful pathogen.