Abstract: The ecological environment problems in the lower reaches of Tarim River in Xinjiang are very severe.To improve the local ecology and environment of the region,18 times of ecological water transports have been arranged in line with the principle of ecological construction and environment protection in the lower reaches of Tarim River since 2000.In recent twenty years,the ecology and environment has been progressively improved because the groundwater level has kept rising with the times of water transports and ecological vegetation restoration has kept going well.In particular,a real breakthrough was created in the lower reaches after water transport and its coverage after the 18th ecological water transports in 2017,which has got heightened attention from various circles of society.The paper analyzed the influence of water transport on the ecological environment in terms of water quantity,water quality,the change of underground water level and the vegetation restoration in accordance with the data of the river sections in the recent 20 years.Besides,a review of the previous researches was done,which will give a reference for the ecological operation and scientific management of the lower reaches of Tarim River.The results show as follows:(1) Through the transported water mainly feed the vegetation and groundwater along the two sides of the river course,the continual water transports are the firm guarantee for the steadily improvement of fragile ecology and environment of the lower reaches of the Tarim River. (2) Water transport has result in the ecology and environment betterment,vegetation restoration,groundwater table uplifting and groundwater quality improving. (3) Water transport at flood season or spasmodic and flexible arrangement for water transport could get the maximum benefit.

Key words: the lower reaches of Tarim River, ecological water transport, ecological environment, water consumption, the change of groundwater