Nowadays, the massive accumulation of plastic wastes has caused serious environmental problems, and supercritical water treatment provides a promising way for the clean and efficient utilization of plastic wastes. In this work, the acrylonitrile-butadiene-styrene (ABS) plastic was selected as the feedstock, and the supercritical water gasification experiments for fuel gas production were firstly conducted from 450 degrees C to 700 degrees C, at 23 MPa. The increase of reaction time, temperature and material ratio (water/ABS) can significantly promote the gasification reaction, and the whole reaction process was obviously divided into three stages: the gasification efficiency rapidly increased firstly, maintaining nearly unchanged then, and restarted to grow. The subcritical water hydrolysis for oil products recovery was also investigated from 375 degrees C to 450 degrees C at 21 MPa, and results show that most of the monomers were converted into more stable substances at long residence time. The optimal reaction condition for monomer recovery was determined to be 400 degrees C and 3 min through the experimental results. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.