The invention belongs to the technical field of desulfurization wastewater, and in particular, provides a desulfurization wastewater microfiltration-nanofiltration-reverse osmosis membrane combined processing system including a desulfurization wastewater triple box, a wastewater collection box, a clarification water box, a first reaction tank, a second reaction tank, a concentration tank, a TMF device, an NF salt-separating device, an NF water-producing box, an SWRO membrane concentration device and an evaporator which are connected successively through pipelines; the TMF device is connected with the concentration tank through a backflow pipeline; a concentrated water outlet of the NF salt-separating device is connected with the wastewater collection box through a pipeline; the clarification water box and the concentration tank are respectively connected to a sludge pool; the sludge pool is connected with a plate-and-frame filter press. The desulfurization wastewater microfiltration-nanofiltration-reverse osmosis membrane combined processing system and technology provided by the invention have the advantages of low cost, simple process, convenient operation and high work efficiency, allow produced water to meet emission standards, also realize recycling of inorganic salts in the desulfurization wastewater and comprehensive utilization of resources, saves energy and is environmentally friendly.