The current paper presented the coliquefaction of coal and Dunaliella tertiolecta to produce liquid fuel with sub-/supercritical water-ethanol as the reaction medium in a batch autoclave at high temperature and pressure. The effects of the ethanol/water volume ratio, temperature, feedstock/solvent ratio, and reaction time on the liquid fuel yield and conversion were carried out. The optimal liquid fuel yield and conversion were 40.29 and 70.62%, respectively, in the sub-/supercritical water-ethanol with ethanol content as 60% (v/v), at 633 K, feedstock/reaction medium ratio of 1:10 (g/mL), and reaction time of 30 mm. The experimental results showed that coliquefaction of coal and D. tertiolecta could not be estimated as a weighted average sum of the pure feedstock. Under the optimal reaction conditions, the synergetic effect values of liquid fuel yield and conversion were 12.53 and 15.74%, respectively. The various physical and chemical characteristics of liquid fuel obtained under the best conditions were determined, and the detailed chemical compositional analysis of liquid fuel was performed using an elemental analyzer (EA) and Fourier transform infrared (FTIR) spectroscopy. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to verify the morphology of feedstock, as well as the residua after liquefaction. The calorific value of liquid fuel obtained from coliquefaction was 36.70 MJ kg(-1). The results indicated that there existed a synergetic effect between coal and D. tertiolecta, which is not only to increase the conversion and liquid fuel yield but also to improve the quality of liquid fuel.