FIELD: biotechnology. SUBSTANCE: invention relates to the field of biotechnology. Disclosed is a method of producing bioethanol from algae. Method involves preliminary formation of biomass, initiation of its decomposition by enzymatic hydrolysis, introduction of yeast into the decaying biomass to form a fermenting solution and separation of the obtained bioethanol. Fresh water plants are used as algae, preliminary formation of biomass is carried out on industrial water of thermal power plant and thermal power plant, enzymatic hydrolysis is carried out using complexes of cellulase, hemicellulase, pectinase and desulphatase at temperature of 45–85 °C due to waste heat of thermal power plant and thermal power plant, and separation of bioethanol is started when level of bioethanol in the fermentation solution is more than 4–9 % of volume. EFFECT: invention provides energy-saving production of bio-ethanol by enzymatic hydrolysis with possibility of cleaning process water of thermal power plant and thermal power plant.