Abstract: modern times, forest resources in Gansu Province were severely damaged, the ecological environment degenerated continuously, the natural disasters occurred frequently, and the economic development was draggled. In period of the Republic of China, people began to concern forestry ecological deterioration in Gansu and study the reasons of it. They found that there were internal relationships between natural disasters and forestry ecological deterioration. The flood at middle and lower reaches of Yellow River and Yangtze River also contributed to the ecological degeneration in Gansu Province. They proposed the methods such as protecting forests, afforestation to resolve these problems. These ideology improved peoples consciousness of forests ecological protection and awareness of maintaining ecological balance, prevented further deterioration of the forest ecosystems and promoted forestry activities such as afforestation, soil and water conservation, sandstorm prevention, etc.