Belonging to the technical field of pharmaceutical analysis and quality control, the invention provides a quality control method for a high optical purity folic acid preparation process. The method has the characteristics of strong specificity, good separation degree, high sensitivity and strong operability, etc. The method provided by the invention is employed for strict control of the optical purity of p-aminobenzoyl-L-glutamic acid, and can acquire folic acid with optical purity of more than 99.9%, and is in favor of the quality control of a whole folic acid raw material production process. At the same time, under the quality control system, few side effect occurs, the folic acid has high optical purity and good stability, and therefore the method can be use for quality control of the folic acid crude drug preparation process.