The present invention discloses a benzoyl formic acid synthesis method comprising the following steps: styrene is used as a starting material for implementation of hydrogen peroxide catalytic epoxidation reaction to produce styrene oxide intermediate, alpha-Hydroxyphenylacetone is obtained by hydrolysis of styrene oxide, and the generated alpha-Hydroxyphenylacetone is further oxidized into the desired product benzoyl formic acid. Advantages of the method are that: by use of the method using a solid base for hydrogen peroxide catalytic oxidation of the styrene substrate to form a styrene oxide precursor material, the use of hydrobromic acid is avoided, industrial production reaction cleanability is improved, product preparation selectivity, overall yield and product purity are improved, reaction condition is mild, reaction time is short, the complexity of the reaction process is reduced and industrialization is easy.