In this study, we compared China's current fuel quality standards with the world's strictest ones then discussed the technical feasibility to upgrade it in China. Based on available data from China National Petroleum Corporation (CNPC), China Petro-Chemical Corporation) CPCC and other enterprises, we have estimated the direct economic cost of upgrading the fuel quality standard as follows (considering gasoline and diesel as one kind):from China Ⅲ to China IV, 142~470CNY/t; from China IV to China V, 142~236CNY/t; from China V to the 5th standard in the Worldwide Fuel Charter (5th Edition), 142~236CNY/t. Using EPA's fuel models and other studies on fuel properties, we chose China Ⅲ, China IV, China V and the 5th Standard in the Worldwide Fuel Charter (5th Edition) as the four main scenarios for this study, which differ in some key parameters such as sulfur, aromatic hydrocarbons and olefin et al, in order to estimate the changes in emission factors of each specific vehicle under the proposed scenarios. Furthermore, keeping the fleet structure of that year unchanged, we selected the years of 2005, 2008 and 2012 to calculate the annual and the accumulative reduction of emissions in the Jing-Jin-Ji region when we upgraded the fuel standard for each year, starting from the best standard available upgrading to the 5th in the Worldwide Fuel Charter. From this study, we found that upgrading the fuel quality standards in China does contribute to the reduction of all kinds of emissions from vehicles hence it reduces the total emission in the whole area, especially for VOC and PM. That reduction is more obvious when the standard before the upgrading is less strict. While, considering different sizes and different composition of the fleet of vehicles in the region, the outcomes for different areas are varied. Combining the costs and the estimated reduction in emissions, it was found that the sooner this policy is implemented, the higher cost effectiveness it has, but the more reduction of emission it will bring at the same time. Hence, according to the findings of this study we suggest that upgrade the fuel quality standards must be carried out as soon as possible even if this may lead to a higher cost.