Pot experiment was conducted to study effects of Cd-Cu-Ni compound pollution on six kinds of soil enzyme activities(urease

invertase

protease

phosphatase

catalase

dehydrogenase).The results showed that six kinds of soil enzyme activities had a significant(p<0.05) or very significant(p<0.01) correlation with Cd-Cu-Ni compound pollution and the influence of Cd-Cu-Ni compound pollution on six kinds of soil enzyme activities was very different.The inhibiting effect of the three heavy metals on six kinds of soil enzymes had a toxicity order form top to bottom: Cd

Cu

Ni.Under combination of Cd-Cu-Ni

Cd and Cu mainly exhibited inhibiting effect

while Ni exhibited stimulating effect mainly.The three heavy metals all exhibited stimulating effect to some extent on phosphatase.There is highly significant negative correlation between Cd-Cu-Ni compound pollution and urease as well as dehydrogenase

so it is feasible to use soil urease or dehydrogenase activities as primary biochemical index to evaluate Cd-Cu-Ni compound pollution.