To assess the effects of global warming on tree radial growth and massive mortality in semi-arid forests,the responses of radial growth and death of Populus davidiana to climate change were analyzed using annual climatology and correlation analysis in Saihanwula,southern Greater Xingan Mountains,Inner Mongolia. The results showed that the radial growth of P. davidiana was significantly negatively correlated with the average temperature and minimum temperature (P<0.05) . The radial growth of P. davidiana decreased when the temperature significantly increased after 1993. The radial growth had significant positive correlation (P<0.01) with precipitation in May but no such relationship with precipitation in other months. The rising temperature accelerated the reduction of radial growth and the death of P. davidiana.