Abstract: During the current rare earth situ leaching process, residual fluid containing rare earth, ammonium sulfate and other pollutants flows into the surrounding farmland soil environment. This article summarizes the research progress and evaluation methods of pollutants' effects on farmland soil bioavailability, providing theoretical basis for leaching agent ammonium sulfate's effect. The effects of rare earth elements and leaching agent ammonium sulfate can supply experiment foundation for biology assessment.