Abstract: A great loss is caused by the inundation of Changjiang River watershed in 1998 because the flood has a great quantity and a long continued time and involves a wide range. It attracts a great attention of the people all over the world. It is well known that the irregular change of climate in 1998 and the reducing of lake regulation capacity are very important reasons to cause the inundation. Based on the field investigation to the flood area, the paper discusses the present situation, contributing factors and the ecological influence of the inundation deeply. It is considered that the root reason of this flood in Changjiang River watershed this year is due to the ecological environment deterioration. Forest resource destruction and the unsuitable engineering construction in mountain areas cause serious soil and water loss that proceed to intensify the disaster influence. Some important prevention and countermeasures on the soil erosion control are put forward in the paper that will support an importa