Abstract: The paper reports that micronucleus test technique of Vicia faba root tips has been used in monitoring the pollution of Fengyu Lake in Jishou City. The results of statistical analysis show that each of the samples can make the micronucleus frequence of Vicia faba go up. The micronucleus frequence in Saziao, the Entrance, the Synthetial Building and the Hospi tal reach 10. 95‰, 13. 58‰, 7.94‰ and 6. 77‰, The micronu cleus frequence in the east of the Bridge, the west of the Bridge, the side of Road and the Exitr each 12. 03‰, 10. 84‰, 8. 05‰ and 12. 76‰. The result shows: Saziao and the Entrance are the mos t serious pollution sources, and the ability of water purification is very weak.

Key words: micronucleus, root- tip of vicia faba, water Pollution