Abstract: The synthesis technology of urea phosphate with wet-process phosphoric acid and industrial urea as raw materials was studied in this paper.The optimal process conditions were determined through orthogonal experiment，which were as follows：reaction temperature was 80 ℃，reaction time was 90 min，and the amount-of-substance ratio of phosphoric acid to urea was 1∶1.The effects of influencing factors，such as cooling method and crystallization process on cooling crystallization of large-particle urea phosphate were studied.Programmed cooling method of ′slow first and quick last′ was selected，by which large grained and even urea phosphate crystals were obtained.The study is of practical meaning for industrial crystallizer designing and for guiding industrial production and operation condition optimization etc..