Abstract: This paper discusses the impact of the single and compound heavy metal contamination (copper, zinc and cadmium) on the germination of alfalfa by cultivated experiments in the concentrations of each heavy metal according to the Chinese Soil Environment Equality Standard.The results indicate that the length of root and bud of alfalfa are obviously stressed when the concentration of Cu and Zn is 20mg/L and 80mg/L respectively.And compared with the controlled sample, the difference is extremely remarkable.Under the compound heavy metals contamination, there is obviously interaction between copper and zinc.Moreover the stress effect of copper and zinc on alfalfa is strengthened by the existence of cadmium.