Abstract: In order to confirm the symptoms, acute injury thresholds and lethal concentrations of plants contaminated by fluorine, and provide theoretical basis for fluorine pollution prevention, the author treated plant seedlings and mature branches by KF solution and KCl solution of different concentrations, observed and recorded damage symptoms and measured fluorine contents of leaves. The results implied that different plants had different damage symptoms after culturing by KF solution. In the same processing time, the higher KF concentration, the more obvious damage they exhibited and higher fluorine content was found in leaves. In different processing times, KF caused different acute injury thresholds and lethal concentrations on the same plant, but the fluorine content in leaves was basically the same when the plant began to appear injury symptoms or died. However, using KCl solution to cultivate plants seedlings and mature branches in the same condition caused no obvious damage symptom. It indicated that fluorine was harmful to the growth of plants. The acute injury thresholds and lethal concentrations of KF were determined according to the concentrations of KF and the time and degree of damage to plant.