Pulse electro-coagulation flotation was used to treat oil wastewater of high oil content. Different operational conditions were examined, including current density, reactive time, electrode distance, pH and pole switching time. Orthogonal tests were carried out to identify the optimal operational conditions for this technique. Considering the treatment cost and efficiency together, the optimal operational conditions were an electrode distance of 3.3 cm, pH of 4, current density of 49.38 mA/cm2, reaction time of 15 min and pole switching time of 10 s. The removal efficiency of oil wastewater under normal conditions reached up to 96.21%. The influences of different factors on removal efficiency were in the following decreasing sequence: pH> current density > pole switching time > reactive time > board distance.