Abstract: During soil drought stress, nature water content of seedlings leaves of Betula platyphylla decreased, the changes of relative water content of which was same as nature water content. Bound water content and the ratio of bound water content and free water content increased significantly, along with the decrease of soil water, soluble protein content decreased and soluble sugar content increased, after soil water was recovered, all of which returned to normal level.

Key words: seedlings of Betula platyphylla, drought stress, water content, bound water content, free water content, soluble protein content, soluble sugar content