The invention belongs to the technical field of medicine, and particularly relates to a synthetic method for ceftazidime side chain acid ethyl ester. The method comprises the following steps: adding sodium nitrite and ethyl acetoacetate into water, adding acetic acid for a reaction, performing extraction, and collecting the organic phase; performing distillation on the collected organic phase under normal and reduced pressure to obtain an oxime compound, performing dehydration treatment on the oxime compound, adding an alcohol, a catalyst and chlorine gas, and performing a chlorination reaction to obtain a chloride; performing a reaction on methanol, thiourea, a phase transfer catalyst, a buffer salt solution and the chloride to obtain an ethyl 2-(2-aminothiazole-4-yl)-2-hydroxyiminoacetate solution; and performing distillation on the ethyl 2-(2-aminothiazole-4-yl)-2-hydroxyiminoacetate solution under reduced pressure to obtain ethyl 2-(2-aminothiazole-4-yl)-2-hydroxyiminoacetate solution and a buffer salt, adding tert-butyl 2-bromoisobutyrate, a condensation catalyst and a solvent, and performing a reaction to obtain the ceftazidime side chain acid ethyl ester. The method is moreefficient, simpler, and more environmentally friendly and has higher quality and yield than a previous processes, and is suitable for large-scale industrial production.