Biomass is the alternative energy, which can apply enery transfer technology to replace fossil fuel. Biofuel can improve compatibility for combustions and strorge. Hydrothermal liquefaction (HTL) is the best technology of treating wet wastes for fuels production. Around 10-20% soild content can be apply in the tranditional Hydrothermal liquefaction technology, and the bio-oil conversion efficiency was below 40%. In this study, we try to develop novel technology for "Hydrothermal liquefaction of wet wastes from waste alga". The results show that around 40% soild content was applied into this novel HTL technology, and the bio-oil conversion efficiency was reached at 45%, at the conditions of 270-320 ℃,5-15 MPa reaction pressure, and 60 min reaction time, whie the heating value of produced bio-oil was 35 MJ/kg. In the furture, the HTL technology can be upscale to commercial in Taiwan and provide new and clean energy sources via waste energy recovery and utilization technologies.