Abstract: Virtual forest can provide a new way for forest management and research.Two key problems about generating virtual forest which is true of law of stand structure have been solved in this paper. One is to analyze and simulate forest spatial data, to research on how characters of tree such as height, diameter and so on were distributed in stand. The other is to construct three-dimensional geometric model of tree with the interactive and parameterized modeling method if forest spatial data are given. In last this paper expounds the generating process of the whole virtual forest.