Hydrothermal liquefaction experiment was performed as follow. One gram of dried Tetraselmis sp. MBEyh01L and 4g of water reacted in a batch reactor at different temperatures (300, 325, and 350°C) and reaction times (5, 10 and 30 min). In order to find optimum conditions which maximize energy recovery and quality of biocrude, we analyze biocrude yield and element composition of feedstock and biocrude. At 350°C and 30 min, there was highest energy recovery (82%) with a high energy density of 37.9 MJ/kg. Also, in this reaction condition, biocrude has lower contents of nitrogen and oxygen. Results showed that reaction conditions of 350°C, 30 min was optimum for maximizing energy recovery.