Abstract:Chinese fir (Cunninghamia lanceolate Hook.) is an important wood species in China. The essential oil obtained by steam distillation from the wood of Chinese fir has been investigated. The components of the essential oil was identified by GC/MS. It has been found that there are 39 compounds in the essential oil in which cedrol is major compound. The purpose of this work is to study the natural resistance of the extractives from Chinese fir against the termite and fungus. The qualitative and quantitative method of damage test and the ability against both the termite and fungus of both the Chinese fir wood and its extractives are detemined by Agar-plate toxicity test and sandblock method in the laboratory.The results of this study are as follows:1. The ability of natural resistance the fungi (Lenzites brabea Pers ex Fr.) and the termite (Reticulitermes chinensis snyder.) is rather considerable. The loss of wood samples in weight attacked by the fungi is 10.1%. According to the classification of the natural decay resistance this level lies between class Ⅰ and Ⅱ (very durable and durable). The rating scale of natural resistance of the wood samples against the termites lies between class Ⅱ and Ⅲ.2. It is shown that the property of the natural resistance against the fungus and termite attributed to the cedrol and the other components of the essential oil. However the ability of the resistance is lower than that of sodium pentachlorideophenate and WP-1.