In the present paper, life cycle analysis of coal based methanol-to-olefins processes in China is performed based on the detailed information of the china's largest project of its kind. The purpose of our analysis is to identify the reduction potentials of the project for the energy/water saving and the emission control. The details of the project are given together with the involved techniques. In our analysis, the water and energy consumptions, CO2/SO2/NOx emissions are all demonstrated in terms of six sub-processes with both the direct and indirect contributions. Based on the analysis, we identify that the coal-to-methanol process consumes a vast amount of water and energy with significant CO2/SO2/NOx emissions. For water/energy savings, methanol-to-olefins process is of litter potential because its consumptions are mainly the indirect ones. The negative effects of CCS should be noticed for the implement in the large-scale coal based chemical engineering due to its significant consumptions of the water and energy. (C) 2017 Elsevier Ltd. All rights reserved.