Abstract: The magnetron sputtering method was used to prepare Ti film at helium and argon mixed atmosphere in order to introduce helium into the film.The influence of He-Ar flux ratio on the Ti film microstructure was studied,and the influence of temperature on the evolution of helium bubbles was analyzed.The dimension of bubble increases with the increment of helium flux while there is a maximum for the bubble density during the process.When the temperature is lower than 0.5 Tm,helium cluster located in the interior of crystal grain congregates to form bubbles which are visible in TEM.The migration and coalescence of bubbles occur when the temperature is higher than 0.5 Tm,while the size of helium bubble increases obviously.