Abstract: The analysis of soil quick-acting potash and slow-acting potash in Datong＇ s seven counties and two districts shows that the average content of quick-acting potash in soil is 105.3mg/ kg, slow-acting potash in soil is 714.6mg/kg. The soil in which the content of quick-acting potash is less than 100mg/kg is over 50%. Through years of experiments and demonstration, it shows that the application of potash fertilizer to crops liking potash such as potatoes, vegetables etc, has clear effect on increasing production and the rate of growth is 8%-20%. In this paper,some rational suggestions on the application of potash fertilizer in Datong area to the major potato yielding field are also advanced.