The study shows that Hg and Cd had a remarkable inhibitory effect on soil urease activity, with Hg+Cd and Hg being the most in extent and intensity, respectively.Urease activity can be an index of Hg or Hg+Cd pollution of soil.The soils were polluted severely when the contents of Hg and Cd in the soil reached 1.613~2.647mg kg^-1 and 481.09mg kg^-1 respectively.In the case of Hg+Cd, the inhibition effect was mainly determined by either of the two elements.Hg and Cd showed weak antagonism in multiple treatments.T emperature and urea concentrat ion could enhance heavy metals' inhibition effect on urease activity.