In order to further reduce the pollution of coking wastewater to the environmental water body, to reduce the environmental pollution tax of enterprises to pay fees, in combination with the actual deepening of the development and application of zero-out-discharge technology of coking wastewater, at the same time, most of the produced water could be recycled and used as the supplement of industrial production water, and the cost of new water consumption could be reduced. The successful application of zero-efflux technology for coking wastewater was developed and implemented in the iron-making plant of Beiying Company by using the pretreatment combined with the primary biochemical system and the ozone ultrafiltration reverse osmosis process. The results showed that the technology can achieve zero dilution and zero discharge in practice, which provides important reference value for comprehensive treatment of coking industry wastewater.