In recent years, eucalyptus plantation is being developed very quickly in southern China and became an important raw material for industrial utilization. But it is necessary to determine the natural decay resistance, durability and ability of anti attack to pests. After both laboratory tests and field trials were applied, the results showed as follows: wood natural decay resistance of eucalyptus in 4～9 years after planted was relatively poor; most heartwood belonged to the moderate class, but sapwood all belonged to perishable class; the ability of wood anti attack to pests were relatively low as the wood was easy to be attacked by beetles and termites. The natural durable life of the Eucalyptus urophylla wood were slightly longer than half a year, and the wood belonged to non durable class.