Abstract: Having probed the green moisture content variation of Cunninghamia lanceolata, a law has been discovered in both vertical and horizontal directions. In vertieal direction, the moisture content of the rhizome is larger than that of the middle part of the trunk, but is less than that of the tip of the tree. In horizontal direction, the sapwood is 1.24 times as large as heartwood. The green moisture content variation law varies inversely in the strength variation type of a single-tree so that the larger the moisture content is, the less the strength is. Therefore, the moisture content of the wood has, to a certain degree, reflected the strength index of the wood.