Plane wave ultrasoft pseudopotential technique based on the density functional theory was used to study the effect of high concentration of oxygen vacancies on the electron life span. Using first-principle theory, the structure of anatase TiO2 was optimized, then the state density was calculated. The result showed that at a constant temperature and with high oxygen vacancy concentration, the life span of electrons in anatase TiO2 declines with the increase of the O vacancy concentration, while the electron concentration has no effect on the electron lifes pan. Meanwhile, the Mott phase transformation takes place when the concentration of oxygen vacancies in anatase TiO2 is high.