The invention relates to a desulfurization waste water recycling and zero discharge system and method. The desulfurization waste water recycling and zero discharge system comprises a desulfurization tower, a filter and a nanofiltration device which are sequentially connected, wherein a scale inhibitor dosing device is arranged at the inlet of the nanofiltration device, the concentrated water outlet of the nanofiltration device is connected with the desulfurization tower, the fresh water outlet of the nanofiltration device is connected with a saline water concentrating device, the fresh water outlet of the saline water concentrating device is connected with a fresh water tank, the concentrated water outlet of the salt water concentrating device is connected with a crystallizer, and the condensed water outlet of the crystallizer is connected with the fresh water tank; a drying encapsulating machine is arranged at the solid outlet of the crystallizer. The desulfurization waste water recycling and zero discharge system has the advantages that desulfurization waste water discharged from the desulfurization tower is filtered and then is fed into the nanofiltration device, nanofiltration concentrated water returns to the desulfurization tower, nanofiltration fresh water is treated by virtue of the salt water concentrating device and then is crystallized by virtue of the crystallizer, the obtained fresh water is recycled in the fresh water tank, and salt is separated out, dried into crystallized salt and transported outside after being encapsulated, so that zero discharge of the desulfurization waste water is realized, quality of the recycled fresh water is improved, and a chemical agent and operating cost are saved.