The invention relates to a synthetic method of disodium creatine phosphate, which is characterized in that the method comprises the following steps: reacting creatine with C1-4 alkyl alcohol to produce corresponding creatine ester, or reacting the creatine with quaternary ammonium base to produce corresponding creatine ammonium salt, then reacting with dibenzyl phosphite to produce corresponding N-(dibenzyloxyphosphoryl) creatine ester or N-(dibenzyloxyphosphoryl) creatine to be hydrolyzed or neutralized by base for obtaining N-(dibenzyloxyphosphoryl) creatine sodium which goes through hydrogenolysis, removing benzyl for obtaining disodium creatine phosphate. The preparation method has the advantages: first, the creatine is prepared into the creatine ester or creatine ammonium salt, which increases the solubility of the creatine in a solvent of subsequent reaction, overcomes the problem that reaction temperature has to be raised, leading to increased by-products due to the poor solubility of the creatine in a reaction solvent existing in a former technique; the dibenzyl phosphite serves as an phosphorylating reagent, which avoids using phosphorus oxychloride with relatively high toxicity and irritation; toxic reagents such as mercuric oxide, etc., are not used in the reaction, thus reducing pollution to environment; the method has simple reaction process, low cost and high production rate.