Abstract: The dynamics of soil fertility of citrus orchards in demonstration area of environmental immigrants，Northwest Guangxi was studied.The results show that the soil fertility level decreases first and then increases.The pH value decreases slightly，and acidity is strengthened.The content of organic matter decreases first and then increases slightly.The content of total N decreases and the content of hydrolysable N，total P，available K and available P have been raised as a whole.The content of total K increases first and then decreases.Finally，the reasons of the soil nutrient changes are explained.