To get the best result from vacuum freeze drying of water-logged wood, it is necessary for objects to find out the best conditions such as chemicals, appropriate concentration of solutionn, impregnation method and etc. Such best conditions could be set up by pre-treatment experiments. Two kinds of wood (Pinus densiflora S. et Z. And Quercus acutissima Carruth) were pre-treated by four methods: 2-step PEG treatment (PEG #200-PEG #4000), sorbitol treatment, PEG #200+PEG #4000 treatment, and sorbitol+PEG #4000 treatment. After those pre-treatment, vacuum freeze-drying was undertaken. Then the effect of dimensional stability were compared. When using 2-step PEG treatment, a solution of 60% PEG #4000 got the best dimensional stability for pine and in case of the oak, a solution of 40% PEG #4000 got the best. Sorbitol treatment got rather good result for the pine only when applied with 40% solution of sorbitol. Sorbitol, PEG #200+PEG #4000 and sorbitol+PEG #4000 treatments to the oak didn't affect on dimensional stability sufficiently.