The invention relates to a system for recycling and treating coking wastewater. The system comprises an electrocoagulation floatation pond, an electrocoagulation floatation dregs-scraping machine, an electrocatalysis oxidation pond, a membrane biological reaction pond, a membrane bioreactor water-discharging pump, a multi-medium filter, a carbon filter, a security filter, a reverse osmosis high pressure pump, a reverse osmosis device, a reverse osmosis water-producing pond, a reverse osmosis water-producing delivery pump, a filter reverse washing pond, a filter reverse washing pump, a reverse osmosis washing pond, a reverse osmosis washing pump, a reverse osmosis concentrated water pond, a reverse osmosis concentrated water delivery pump and a pipeline mixer, wherein the electrocoagulation floatation pond is internally provided with an electrocoagulation electrode and an electric floatation electrode; the electrocatalysis oxidation pond is internally provided with an electrocatalysis oxidation electrode; and the membrane biological reaction pond is internally provided with a membrane bioreactor. The treatment system has stable treatment effect, low production and operation cost, and convenient and simple operation, can treat and utilize the water drained from a biochemical precipitation pond, avoid the physical and chemical treatment section after the normal biochemical treatment, avoid using a large amount of medicament, reduce the sludge treatment amount of the system and lower the operation cost of wastewater treatment.