China has been importing a large amount of Mongolian Scotch Pine （ Pinus sylvestris var. mongolica ） logs and lumber from Russia for several years. Since Mongolian Scotch Pine is easily infected by mold and sapstain fungi, a preservative, TBQ, was prepared following development of the treating equipment by the authors. A series of experiments were conducted to determine the effectiveness of TBQ treated lumber. Results showed that the TBQ treated lumber could be well protected from mold and sapstain, and their antimold and anti stain effectiveness could reach 98% after being immersed in TBQ solution with concentration of 6% for 1 hour. The authors suggested that Mongolian Scotch Pine logs or lumber should be treated immediately after logging or sawing. It is necessary to set up treating equipment near logging spots or import ports before the wood are transported long distance to domestic wood markets.