Preparation of catalyst CRBA used for biodegradation polymer synthesis

A process prepares which is a metal-free innocuous organic compound catalysis-benzoic acid creatinine L guanidine. The invention adopts direct synthesis process, which using creatinine L and benzoic acid as raw material, using water as solvent, wherein molar ration of which is strictly controlled is 1:1-1:2, reaction temperature is 30-80 DEG C, cooling down to ambient temperature after reaction, removing solvent through decompression and rotary steaming, conducting vacuum drying for solid which is obtained in normal temperature, and finally obtaining white benzoic acid creatinine L guanidine. The technology process of the invention has the characteristics of simple technology operation, non pollution, low productive cost of product, high product yield (>=96%) and high product purity (>=98%) through adopting free catalysis and direct synthesis in water solution.