Abstract: Ferrate is a new green purifying agent，which has a wide range of uses and applications in water treatment.To achieve the pilot production of ferrate，a diaphragm cell of continuous feed was developed.The anolyte solution can be recycled in the diaphragm cell，which was applied to the continuous and on-line production of ferrate.Not only the analytical methods of total iron and Fe（Ⅵ），but also purification and drying process of ferrate were studied.The analysis of total iron in the ferrate was compared between mercury-free method and the traditional mercury method，and the results were very close.Meanwhile，the content of Fe（Ⅵ） analyzed by the improved chromite method was consisted with that of traditional arsenite method.All aspects of fresh electrolyte of continuous electrolysis were superior to that of electrolyte recirculation.The preparation process after improvement became much simpler for ferrate purification，less use of organic solvents，and lower cost of production.

Key words: potassium ferrate（Ⅵ）, on-line continuous preparation, electrolysis, mercury-free iron determination, purification