Abstract: Progress in studies for the last decade on the relationship between solar activity and decadal climate change, is reviewed. First, recent observations and simulations for the in fl uences of solar activity on the global and regional temperature, monsoon and precipitation, and the regional climatic modes including the Atlantic Oscillation (AO), the North Atlantic Oscillation (NAO), ENSO, and the Quasi Biennial Oscillation (QBO) are reviewed and summarized. Second, three mechanisms proposed to explain these climate observations are described, including the effects of variations in total solar irradiance, ultraviolet radiation and energetic particles. Finally, we have presented some important and unsolved problems for future research.