Abstract: Aiming at the shortcome of traditional Fe-C micro-electrolysis reactor (1^#), which was easy to be blocked and short-circuiting current, an improved honeycombed micro-electrolysis reactor (2^#) was designed. The effects of two kinds of reactors on the wastewater treatment from an oil production plant in Shengli Oilfield were compared. The results showed that: under the conditions of pH 4, inlet velocity 0.2 m/s, reaction height 40 cm, and influent COD 480 mg/L, the 2^# and 1^# reactors' reaction time were 30 min and 60 min, the removal rate of COD were 86% and 70%, and the turbidity removal rate were 98.4% and 94% respectively. It can be seen that the improved flow state of 2^# reactor increased the contact area between wastewater and electrolytes, reduced the hydraulic retention time, and improved the removal rate of COD and turbidity. The pilot-scale application results in Changqing Oilfield showed that the average removal rate of suspension, viscosity, total iron and total hardness in 2^# reactor for different concentration wastewaters were 38.78%-42.31%, 12.54%-32.38%, 69.23%-71.17% and 37.29%-61.76% respectively, which were greatly improved, compared with 1^#, and the treated water could meet the technological indices set by the oilfield produced water reinjection regulation.