A method for extracting beta-carotene comprises the following steps: (1) fermenting microbial thalli containing beta-carotene to obtain a fermentation solution containing beta-carotene, and processingthe fermentation solution to obtain dry thalli with the water content being less than 10%; (2) uniformly adding the dry thalli into serially connected reaction columns; (3) adding an organic solventto the serially connected reaction columns, and allowing the organic solvent to sequentially go through the serially connected reaction columns in order to extract the beta-carotene from the thalli; and (4) collecting the obtained beta-carotene extract, and carrying out desolvation, crystallization, filtration and vacuum drying to obtain beta-carotene crystals. Traditional batch extraction is replaced with continuous extraction, so the beta-carotene extraction efficiency is effectively improved. The reaction columns are monitored in real time in the extraction process, so full extraction of the thalli is ensured, and ineffective extraction after completion of extraction of beta-carotene from the thalli is avoided.