China has faced the dual pressures of global climate change and deterioration of domestic environment,gradually clearlydefined that the market mechanism is an effective way to improve the level of climate and environmental governance,carbon emission trading is a typical form,however,the current research on the comprehensive consideration of its carbon emission reduction and green development effects are relatively deficient. Therefore,this paper takes the carbon emission trading pilot policy as an example, differentiate its carbon emission reduction and regional green development effects,separately constructed the carbon intensity and the Malmquist-Luenberger index,which bad outputs containing global emissions and regional pollutants,based on the panel data of 30 provincial and regions from 2008 to 2015,using double difference method to analyze the influence of carbon emission trading policy on them,and further examine the synergy path and mechanism. The results showed that: ①China's carbon emission trading policy has promoted the decline in carbon intensity in the pilot areas while also promoting the green development of the pilot areas; ②The synergistic emission reduction effect is mainly achieved through SO_2 ; ③The main mechanism that China's carbon emission trading policy simultaneously achieve carbon emission reduction and regional green development is technological upgrading. These conclusions indicate that: China should continue to promote the construction of the national carbon trading market,promote regional environmental improvements while achieving the goal of global carbon reduction; Fully consider the synergy between carbon emission trading and pollutant emissions trading,in the process ofcollaborative reduction'the greenhouse gases and regional pollutants,comprehensive consideration the synergies and abatement costs to achieve the dual goal at the lowest cost; Adopting various means to promote green development,in addition to actively absorbing the experience and lessons of the pilot phase of carbon trading,it should also work together with other environmental protection policies to complement each other,give full play to itsinvisible hand'market adjustment ability and the government's overall control ability,and jointly promote regional green high quality development.