In low carbon economy era, the carbon finance based on carbon market is flourishing and pushing forward the development of carbon market. By analyzing the situation of the world and China's carbon market, as well as the benefits and risks commercial banks will get when they participate in carbon market, the paper indicates that China should establish a carbon finance system using commercial banks as a platform to promote the development of carbon market. The roles of commercial banks mainly include: to strengthen the financial support for the development of low-carbon economy; to strengthen the innovation of carbon derivatives products and risk prevention; to involve in the carbon emissions trading intermediary services actively.