Abstract:The actual runoff reduction of soil and water conservation in Loess plateau is about 1.0 billion m3. How many would be the water consumption after large-scale harness? It is pointed out that the number is about 2.0 billion m3, 4.0 billion m3 and 5.0 billion m3, respectively in 2010, 2020 and 2050, through multi-method analysis.