Synthetic process of cefixime and its key intermediate 7-Amino-3-ethenyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid (7-AVCA) was introduced.Enzymic Hydrolysis was a substitute for Chem. Cleavage of Mismatch.With studying and improving, the synthetic route was finalized as follows: taking 4-methoxybenzyl-3-(chloromethyl)-8-oxo-7-(2-phenylacetamido)-5-thia-1-azabicyclo[4,2,0] oct-2-ene-2-carboxylate (GCLE) as the starting material, the key intermediate 7-AVCA was synthesized by the step of enzyme hydrolysis.The target compound was obtained with total yield of 64%.Environmental problems were solved by the improved process and the high-quality 7-AVCA was of advantage to get the better cefixime with increasing contents, improving stability and low impurity level.The structure of cefixime was confirmed by1H-NMR, IR and UV, and the HPLC purity was above 99%.With the above process, Cefixime was synthesized with a simpler procedure and a higher yield comparing with the report in the literatures.The process of enzyme hydrolysis contributing to energy conservation and environment protection was suitable for the industrialization.