Abstract: To understand the difference of the betulin content in different parts and provenances in Betula platyphylla Suk., the methods to extract betulin were selected, and an accurate HPLC method to detect betulin content was used. The results were as follows:Betulin contents of the same birch bark through 4 extraction methods,namely Soxhlet extraction, supersonic wave, extraction refluxing and chloroform extraction were 240.25, 239.57, 207.88 and 194.09 mg/g respectively; The contents of betulin in different parts of birch were outer bark>branch bark>inner bark>bud>leaf>root>pollen; Betulin contents in the bark of eight-year old birches of 13 provenances were detected, and their range was from 132.45 to 257.11 mg/g. Analyzing the relations among betulin content and growth status, geographical location and climatic factors, it was found that the effect of growth status on betulin content was not significant, and betulin content was not only affected by self-provenance and heredity background but also by geographical location and climatic factor.

Key words: Betula platyphylla Suk., betulin, extraction methods, different parts, provenances