The experiment of planting Pennisetum purpureum in intensively eroded slope land was made in the district of Hetian, Changting County, Fujian, and the pot experiment was made simultaneously to investigate the biological characteristics of P. purpureum and its effects on soil physical properties. It was discovered that P. purpureum possesses the characteristics of quick tilling, flourishing system of roots and high adaptability so as to improve soil physical properties. The benefits of planting P. purpureum in eroded slope land were notable in soil and water conservation. P. purpureum is a type of herbaceous species worth popularization.