The utilization of water hyacinth has attracted great attention for its invasive problem. The hydrothermal liquefaction of water hyacinth was conducted at moderate temperatures (240-340 degrees C). Distribution and identification of the products were investigated by using gas chromatography-mass spectrometry and elemental analysis. The results showed that the yield of total oil increased with the increasing temperature, peaked at 320 degrees C, then decreased afterwards. The decomposition of water hyacinth to form small molecular compounds was the dominated process at lower temperatures, while more secondary polymerization reactions happened at temperatures over 280 degrees C. Compositions of oil products were very complex and varied with temperature. Higher temperatures are a benefit for production of high value-added chemicals, such as phenols and cyclopentenes in water soluble oil. This could be the evidence to refine biofuel or biochemicals from water hyacinth by hydrothermal liquefaction.