The invention belongs to the field of medicine preparations, and particularly relates to a preservation method of folic acid. The preservation method comprises the following steps of separating natural folic acid from foods, adding starch into the folic acid, and uniformly mixing the folic acid and the starch, so as to obtain a mixture A; dripping mangosteen extract into the mixture A in the previous step, and uniformly mixing the mangosteen extract and the mixture A, so as to obtain a mixture B; mixing tomato and carrot, squeezing into juice, adding lotus root starch, and uniformly stirring;uniformly mixing the matter obtained in the previous step and the mixture B, and drying under the vacuum condition, so as to obtain a mixture C; uniformly mixing honey and flour, so as to obtain a mixture D; adding the mixture C into the mixture D, uniformly mixing the mixture C and the mixture D in a vibration way, and drying under the vacuum condition, so as to obtain the completely sealed folicacid. The preservation method has the advantage that the folic acid can be sealed and preserved in a multi-layer anti-oxidizing matter coating way.