Copper triazole was chosen to treat the sheathing plywood using vacuum processes at various pressures and treatment duarations. The durability and mechanical properties of the treated samples were examined. The results revealed that parameters of the optimized treatment were: vacuum in-0.04 MPa for 10 minutes, then soaking at the atmospheric pressure for 10 minutes. The testing result showed that the preservative-treated plywood presented a high level of durability with less than 5% of mass losses; and the modulus of rupture and modulus of elasticity of the samples met the requirements on sheathing plywood for wood-frame structures of the Chinese national standard GB/T 22349—2008.