Abstract: Five wood rot fungi were used to decay 300 mature trees of white birch. The decaying susceptible and resistant populations in 10 trees each with the highest and lowest weight loss were selected, in which some main chemical components in wood such as lignin and cellulose etc. were tested. The result showed that the birch wood with lower moisture, cellulose and lignin content was hard to be decayed by Irpex lacteus, and those with lower lignin content and higher benzene-alcohol extraction was more inappropriate by Pholiota adipose, while the wood with higher lignin content was less easily attacked by Fomes fomentarius and Piptoporus betulinus, but there was no special favor by Coriolus versicolor in wood chemical components to be found. The 1％ NaOH extraction in white birch wood had negative correlations with moisture and cellulose. The moisture and cellulose, benzene-alcohol extraction and total phenol, total phenol and total flavonoids and lignin have positive correlations in the susceptible populations of white birch wood. This paper would provide some useful information in future study in the course and mechanism of wood decaying by rot fungi, and difference in the physical and chemical characteristics of the wood between the decaying susceptible and resistant populations.