Folic acid(folate) is one of the B vitamins that is essential for the human body. In the paper, the molecular structure of folic acid and its main forms , as well as the content of folic acid in common foods were introduced. The sample pretreatment methods such as chemical method and enzymatic hydrolysis method were described. The chemical method mainly utilized the characteristics that folic acid was easily soluble in neutral or alkaline solution. The enzymatic hydrolysis method mainly used a combination of protease and amylase to treat the sample, so that the folic acid combined with protein, starch and the like was fully hydrolyzed. The common methods for detecting folic acid, such as microbial method, fluorescence analysis method and high performance liquid chromatography (HPLC), were reviewed. The microbial method mainly used the principle that folic acid was a necessary nutrient for growth of Lactobacillus rhamnosus. The principle of the fluorescence method was that the folic acid had a pyrazine-pyrimidine ring, which had a special absorption spectrum and redox characteristics. HPLC was characterized by high efficiency and precision, especially ultra-performance liquid chromatography-mass spectrometry/-mass spectrometry (UPLC-MS/MS), which can quickly determine different forms of folic acid. Factors affecting the stability of folic acid and measures to increase folic acid intake and stability were explored. Establishing accurate detection of folic acid content in food and the presence of folic acid has urgent practical significance.