The invention relates to a synthesis method of a compound of 7-hydroxymethyl-2,5-diazaspiro [3,4] octane-2-dimethylethylester, and mainly solves the technical problem that no industrial method suitable for industrial synthesis exists in the prior art. A compound 1 and triethyl-phosphite are used as raw materials for synthesizing and obtaining the final compound through eight steps. A reaction formula is shown in the specification.