NOVELTY - Culturing Chlorella biomass comprises (i) adding culture medium into a closed circulation pipeline of a culture device, introducing carbon dioxide and circulating culture medium and inoculum in the closed circulation pipeline under a light irradiation condition, (ii) circulating the culture medium and inoculum mixture in a heat exchange device, adding potassium hydroxide solution, and culturing, (iv) clarifying the Chlorella suspension, and (v) adding mineral medium and culturing.    USE - The method is useful for culturing Chlorella biomass (claimed).    ADVANTAGE - The method utilizes waste mineral culture medium, which saves resources, improves culture speed and increases biomass yield.    DETAILED DESCRIPTION - Culturing Chlorella biomass comprises (i) adding culture medium into a closed circulation pipeline of a culture device, introducing carbon dioxide into the culture medium, and circulating culture medium and inoculum in the closed circulation pipeline under a light irradiation condition, (ii) circulating the culture medium and inoculum mixture in a heat exchange device at 36 degrees C under pH of 8.5, adding potassium hydroxide solution, and controlling the average concentration of the Chlorella culture liquid to 0.5 g/l, (iii) introducing mixed gas of carbon dioxide and air, where the volume concentration of mixed gas in carbon dioxide is 10%, the flow rate of the mixed gas is 500 l/hour, simultaneously turning light source, determining illumination intensity of 6000 lux of the culture device uisng a photoreactor, adjusting pH of the Chlorella suspension liquid is 9.4-9.6 and continuously culturing for 12-24 hours, (iv) clarifying the Chlorella suspension to obtain gummy precipitate and secondary culturing, and (v) incubating the clarified liquid for 40 hours, when concentration of Chlorella culture liquid is 3 g/l, the recovery of suspension from the circulation pipe is 5 l/hour, simultaneously adding mineral medium into the circulation pipe, where the amount is 5 l/hour, increasing illumination intensity to 6000 lux and culturing