Chemical compositions of the wood of Betula platyphylla were studied, which grew in five natural stands of the Northeast of China. The results showed as follows:the chemical compositions among the populations were different obviously, except 1% NaOH extraction, holocellulose and pentosan content. And the variation in each population was quite high, which could provide the possibility for selection among and within populations for pulpwood of this species. A significant positive correlation between the content of ash and benzo-alcohol extraction of the wood existed among the populations. Besides, the holocellulose and pentosan content were also great positively correlated each other in the wood. Some negative correlations could be seen between the content of ash, benzo-alcohol extraction and longitude, as well as between lignin and latitude, also some positive relations between the holocellulose, pentosan content and latitude. That means the birch from high longitude and latitude areas will have lower content of the ash, extraction and lignin, higher content of the holocellulose and pentosan in the wood.