The invention discloses a device and method for treating and recycling printing and dyeing wastewater, relating to printing and dyeing wastewater treatment and providing a device and method for treating and recycling printing and dyeing wastewater on the basis of a nano catalytic electrolysis and membrane technology, with the advantages of high removing rate of CODCr, less consumption of chemical agents, less produced sludge, more thorough treatment and high water recycling rate. The device is provided with a coarse grid filtering machine, an adjusting pool, a hydraulic sieve, a desulphurization reaction tank, a nano catalytic electrolysis machine, a flocculation reaction tank, a settling tank, an air flotation device, a biochemical reaction tank, a secondary settling tank, a secondary nano catalytic electrolysis machine, a filter, a pressure filter, a membrane system and a circulating water tank. The method comprises the following specific steps of desulphurization, nano catalytic electrolysis, flocculation, biochemical treatment, secondary catalytic electrolysis, filtering, and membrane separation.