The environmental effect analysis for the ethylene process from five production processes including crude oil,crude coal,raw material,ethylene and electricity in China was studied through life cycle assessment (LCA) approach by IMPACT 2002+,which covered thirteen impact factors. It was found that the impact of non-renewable energy,global warming,respiratory effects and aquatic acidification played a dominant contribution. The most contribution from non-renewable energy was crude oil. The effect of SO_2,NO_x,CO_2 produced by ethylene production and material production as well as CH_4 released from oil extraction were the main contributors on the environmental impact,which were the key factors for reducing the environmental effect for ethylene process in China. The environmental impact of ethylene production using naphtha as raw material was smaller than that from light hydrocarbon. However,coal to olefin process should be further improved because of larger environmental impact. It can also be seen that consumption of resource and emission of pollutants have made great progress after several decades of development.