We have proposed a new scheme for brown coal conversion consisting of hydrothermal extraction and hydrothermal gasification process. To examine the possibility of the process, four kinds of low rank coals were extracted by water at 300 and 350℃. The extraction yields of Loy Yang (LY), Wara (WR), Berau Binungau (BB), and Thai Lignite (TL) at 350℃ were 54,48,42, and 44wt%, respectively. The residue obtained showed lower hydrophilicity and higher calorific value than the parent coal, being dewatered partially and upgraded. It was confirmed that the proposed process is promising for effective conversion of various low rank coals.