Hydrothermal liquefaction is a favourable process to convert high moisture lignocellulosic biomass into alternative liquid oil. The merits of liquid fuels are widely known due to their high energy content, transportability and applicability. Among other thermochemical conversions, HTL allows biomass to be processed without drying at a temperature of a few hundred degrees lower than the one of required for pyrolysis. It is currently well-known that reaction temperature and reaction time affect biomass conversion and product yields during HTL, while adjusting the biomass concentration has correlated with energy savings for further upgrading steps. Rice husk was used for the production of bio-oil by HTL using water and ethanol as catalyst. The quality as well as quantity of bio-crude can be improved by two routes: One approach is catalytic hydrothermal processing with homogeneous catalysts such as alkali catalysts or organic acids, alcohols and another is heterogeneous catalysts such as zeolite or supported metal catalysts. Use of Catalysts in HTL process can increase the bio-oil yield form HTL process. Moreover, use of catalyst also resulted in the decrease in oxygen and nitrogen contents of bio-oil and consequently increases in its heating value.