In this paper,the developments of study on characteristics and mechanism of ozone variation and its climate effect are reviewed.The amount of tropospheric O3(in NorthHemisphere)is increasing,that of stratospheric O3is decreasing and the total ozone amount also is decreasing which show the trend of global ozone variation.The main reason is that the O3precusors,such as NOx,NMHC,CO,CH4,are increasing due to human activities and the species(NOx,H2O,N2O,CFCs)which can destroy stratospheric O3are increasing.The enhancement of tropospheric O3will warm the ground surface and the lower atmosphere and the depletion of stratospheric O3may warm or cool the ground surface and lower atmosphere.It is a very effective way to use the global or regional climate model coupled with a atmospheric chemistry model for study on ozone variation and its climate effect.