Abstract: As a low cost, high efficiency and broad perspective technology, electrocoagulation has been proved notable in the treatment of severely polluted industry water, domestic sewage etc. ,but the research for the treatment of slightly polluted water was less. Through test study on river waters that were in batch treatment by electrocoagulation, this paper analyzes the feasibility of slightly polluted water by electrocoagulation and discusses the influence of electrode distance change on the treatment effect. The results show that the electrocoagulation treatment technology can be used in the purification of slightly polluted water; under the current density of 17.75 A/m2, the electrode distance of 1.5 cm and 30 min of reaction time, the chrominance removal rate of polluted water is 73.76%, the removal rate of turbidity is 76%, the removal rate of suspended solids is 85.71%, the removal rate of COD is 42.86%, and the total phosphorus removal rate is 61.36%. In the electrocoagulation treatment, the distance between the electrodes has a significant effect on the color, turbidity, suspended solids and total phosphorus removal efficiency of micro-polluted water.