Abstract: 1. The Sand-Block Method was adopted for the present for the tests of toxicity of water-borne preservative against wood fungi.The results of the toxicity of six formulation preservatives against Polystictus versicolor(L.)Fr.are summarized as follows: By the toxicity of Borax/Boric acid/Sodium fluorid/Chrome/Copper(i.e.B-B-F-Cr-Cu),B-B-F-Cr-Zn(Zine)and Zn-Cr-As(Arsenic),the threshold retention (T.R.3.0—4.0 kg/m³)were higher,while by that of Cu-Cr-As(T.R.1.5—3.0kg/m³)was found highest. As a result of leachability the toxicity of Zn-Cr-As and B-B-F-Cr-Ca appeared mostly higher than that of B-B-F-Cr-Zn.Their T.R.of the former two were 5.5—6.5kg/m³,but the latter was 6.5—11.5kg/m³.From among the T.R.of Cu-Cr-As (4.0—5.5kg/m³)was the highest. In regard to the toxicity and leachability(five days),the six formulation preservatives against Chaetomium globusum Kune.con be arranged in three groups:The toxicity of Cu-Cr-As belongs to the highest rank,that of B-B-F-Cr-Cu to the second,also these of B-B-F-CrZn and Zn-Cr-As belong to the third. 2. Using Sand-Block Method for the tests of toxicity of water-borne preservatives against termite(Reiculitermes speratus Kolbe)was the toxicity of B-B-F-Cr-Cu and Cu-Cr-As shown higher than that of Zn-Cr-As. 3. Six preservatives are not corrosive for iron.