Two kinds of waterborne preservatives, Ammoniacal Copper Quaternary （ACQ） and Copper Triazole （CuAz）, were used to treat Siberian White Fir （Abies nephrolepis） logs by pressure impregnation. The influence of preservative concentration and post-drying style on the properties of the treated wood was analyzed in this paper. A statistical t-test revealed that under a given experimental condition, MOE and MOR of wood samples had changed only slightly after the preservative treatment. However, compared with control samples, the MOR of the wood treated with ACQ decreased, while the MOR of CuAz treated wood also decreased, but in a less obvious way, due to relatively low retention. The MOE of the treated wood was slightly higher, or the same, as that measured before treating.