The utility model provides a sewage treatment system which comprises an oil separation tank and a water basking tank, the oil separation tank is communicated with the water basking tank through a communicating pipe, one end, extending into the oil separation tank, of the communicating pipe is further communicated with an oil separation section, the oil separation section is located in the oil separation tank, and a preset included angle is formed between the oil separation section and the communicating pipe. Oil is prevented from entering the communicating pipe through the end opening of the oil separation section and flowing into the water basking pool, the content of the oil in the water basking pool is reduced, and the evaporation speed of water in the water basking pool is increased.