The production of bio-oil via catalytic HTL of D. tertiolecta was carried out over metal/CNTs. The optimal D. tertiolecta conversion was 95.78% with bio-oil yield of 40.25 wt.% over Co/CNTs. A plausible reaction mechanism of the main chemical component in D. tertiolecta was proposed. The catalyst type affected the chemical composition and boiling point distribution of bio-oil.