Improved wastewater pretreatment system

The invention discloses an improved wastewater pretreatment system which comprises a collecting tank, a settling pond, a micro-electrolytic cell, an oxidation pond and an immediate pond, wherein the micro-electrolytic cell, the oxidation pond and the immediate pond are arranged between the collecting tank and the settling pond; wastewater is introduced into the collecting tank, and then is introduced into the micro-electrolytic cell through a mixer; sulfuric acid is introduced into a mixer; an iron-carbon filler is contained in the micro-electrolytic cell; and wastewater can be subjected to micro-electrolysis, is introduced into the oxidation pond for further full reaction, introduced into the immediate pond and the settling pond to precipitate reacted impurities in the wastewater and finally introduced into subsequent existing biochemical treatment systems for further treatment, wherein alkali liquor is added to the immediate pond. By adopting the micro-electrolytic cell, heavy metal ions and high-chroma and