The invention relates to a synthetic method of a 2,2-diethoxy 
acetophenone photoinitiator, which comprises the following steps: a, synthesizing 
ethyl nitrite, namely mixing 
ethanol with 28 percent of 
aqueous solution of 
sodium nitrite in a reaction kettle with mechanical stirring and a gas ingress 
pipe, dripping 20 percent dilute sulphuric acid into the mixture at the temperature of between 20 and 30 DEG C to generate 
ethyl nitrite gas, and directing introducing the generate 
ethyl nitrite gas into the step b for reaction, wherein the 
molar ratio of the 
ethanol to the 
sodium nitrite to the dilute sulphuric acid is 1.00:1.09 to 1.68:1.10 to 1.18; and b, synthesizing 2,2-diethoxy 
acetophenone, namely introducing the ethyl 
nitrite gas generated by the step a into 
acetophenone and 36 percent 
hydrogen chloride ethanol solution, and neutralizing the mixture by using 
sodium hydroxide solution after a reaction ends to prepare finished products, wherein the 
molar ratio of the acetophenone to the 
hydrogen chloride ethanol solution is 1:1. The synthetic method is simple and convenient in process and high in product yield and is suitable for industrial production.