The invention discloses a method for obtaining lactate from a lactic acid fermentation liquor. According to the method, the lactic acid fermentation liquor is taken as an initial material, filtering,concentrating, acidifying, esterifying and the like are adopted to obtain high-purity lactate. Different from traditional lactate synthesis in which crude lactate and alcohol are used as raw materials, the method for obtaining the lactate from the lactic acid fermentation liquor directly starts from the lactic acid fermentation liquor and achieves obtaining of the lactate product through the stepsof filtration, concentration, esterification, bipolar membrane electrodeionization, extractive distillation and the like, a refining process of lactic acid is omitted, meanwhile, salts in the fermentation liquor can be effectively removed, and the method has low production cost. By using a bipolar membrane, on one hand, the pH value of the system can be reduced, so that the esterification reaction is more complete, and on the other hand, the energy consumption of distillation can be reduced due to the removal of the salts from a deionizer esterified clear liquid. The lactate product obtainedby the method disclosed by the invention is high in purity and can be used for synthesizing light stabilizers, high-grade coatings, bactericides and medical intermediates.