The invention relates to the technical field of biology, in particular to a method for producing beta-farnesene. The method for producing the beta-farnesene includes steps of S1, removing impurities from molasses and purifying the molasses; S1, constructing beta-farnesene recombinant host cells; S3, inoculating the recombinant host cells into culture media with the impurity-removed and purified molasses and carrying out heterologous induction expression to synthesize the beta-farnesene; S4, increasing the yield of the beta-farnesene by means of fermentation control. The method for producing the beta-farnesene has the advantages that the molasses which is low in cost is used as a main raw material, recombinant Escherichia coli is used as a production strain for producing the beta-farnesene,accordingly, the fermentation period can be shortened, and the production cost can be reduced; the beta-farnesene is detected by methods for detecting the beta-farnesene in fermentation liquor by theaid of gas chromatographic processes, and the concentration of the beta-farnesene in the fermentation liquor can reach 20.5 g/L after fermentation is carried out for 72 hours.