Oilfield sewage treatment method and device

The invention relates to the technical field of sewage treatment, in particular to an oilfield sewage treatment method and device. The treatment method comprises the following steps: (1) carrying out multi-stage three-phase separation treatment on to-be-treated oilfield sewage to obtain oil, mud and sewage; and (2) sequentially carrying out electric flocculation treatment and electrochemical oxidation treatment on the sewage. The treatment device comprises a multi-stage three-phase separator, an electric flocculation reactor and an electrochemical oxidation reactor, wherein the water outlet of the multi-stage three-phase separator is connected with the water inlet of the electric flocculation reactor through a pipeline, and the water outlet of the electric flocculation reactor is connected with the water inlet of the electrochemical oxidation reactor through a pipeline. According to the oilfield sewage treated by the method or the device, the removal rate of COD reaches 90% or above, the removal rate of petro