A　tree　geometric　modeling　method　based　on　the　theory　of　L-systems　was　proposed　in　this　paper,　which　was　faithful　to　the　plant　morphology　and　the　physiological　ecology　of　tree　growth　process.　Under　its　guidance　and　restraints,　the　dual　purposes　of　＂to　restore　status　truly＂　and　＂to　simulate　processes　scientifically＂　were　reached.　A　method　to　compound　L-system　rule　from　organ　scale　to　the　whole　tree　scale　was　proposed,　which　could　make　the　plant　morphological　and　growth　rule　be　reused　easily.　The　function　and　architecture　of　LSTree　software　was　designed.　It　was　developed　with　VC++,　OpenGL　Graphics　standard,　VRML　(virtual　reality　modeling　language)　and　Microsoft＇s　MSXML　application　programming　interface.　The　system　has　many　functions　such　as　input　and　output　of　tree　model,　three-dimensional　display　of　trees,　simulation　of　the　tree　growth　process,　etc.　It　provides　a　better　human-computer　interaction　and　a　flexible,　scientific　way　to　manage　and　organize　the　model.　The　system　is　useful　in　many　fields　such　as　education,　propaganda　and　scientific　research　on　botany　and　ecology,　precision　agriculture.