紫茎泽兰入侵到宏大地表负地形的喀斯特退化天坑后,会通过改变其立地环境的土壤微生物群落来影响退化天坑的植物多样性、群落演替与自然生态恢复.以云南沾益天坑群的典型退化天坑巴家陷塘为研究区,选择不同生境的紫茎泽兰根系土壤,采用Biolog微平板法探究紫茎泽兰根系土壤微生物群落特征.结果表明:　受退化天坑内生境异质性影响,紫茎泽兰的入侵程度表现为坑坡灌草地＞坑底草地＞坑坡林地＞坑口灌草地,并且不同生境的紫茎泽兰性状特征存在差异;紫茎泽兰根系土壤微生物代谢活性、优势度指数、丰富度指数、均匀度指数与其入侵程度具有一致的变化趋势,且坑内外差异显著;糖类和氨基酸类为土壤微生物利用的主要碳源;不同生境的草本层植物α多样性与土壤微生物群落多样性存在相关性.紫茎泽兰根系土壤微生物群落多样性会随入侵程度的增加而显著提高,形成有利于入侵定植的微环境.未来退化天坑经过植物群落演替和自然生态恢复,最终形成地下森林顶极群落,可能使紫茎泽兰在退化天坑中消失.After　invading　the　grand　negative　landform　karst　degraded　tiankeng,　Eupatorium　adenophorum　will　affect　the　plant　diversity,　community　succession　and　natural　ecological　restoration　of　degraded　tiankeng　by　changing　soil　microbial　community.　Taking　the　degraded　tiankeng　＂Bajiaxiantang＂　as　the　research　area,　the　soil　around　E.　adenophorum　roots　in　different　habitats　was　selected　to　explore　the　microbial　community　characteristics　of　E.　adenophorum　roots　using　the　Biolog-ECO　micro-plate　method.　The　results　showed　that　the　invasion　degree　of　E.　adenophorum　was　in　order　of　pit　slope　shrub-grassland　＞　pit　bottom　grassland　＞　pit　slope　forest　＞　pit　head　shrub-grassland.　The　characteristics　of　E.　adenophorum　varied　among　different　habitats　due　to　habitat　heterogeneity.　The　change　of　microbial　community　metabolic　activity,　dominance　index,　richness　index　and　evenness　index　of　E.　adenophorum　roots　was　closely　related　with　the　invasion　degree,　with　significant　diffe-rence　between　inside　and　outside　of　the　tiankeng.　Amino　acids　and　polymers　were　the　main　carbon　sources　utilized　by　soil　microorganism.　The　α　diversity　of　herbaceous　plants　in　different　habitats　were　correlated　with　that　of　soil　microbial　community.　The　diversity　of　soil　microbial　community　around　E.　adenophorum　roots　increased　significantly　with　the　increases　of　invasion　level,　which　could　form　a　microenvironment　conducive　to　invasion　and　colonization.　In　the　future,　the　degraded　tiankeng　would　eventually　form　the　climax　community　of　underground　forests　with　community　succession　and　natural　ecological　restoration,　which　might　result　in　the　disappearance　of　E.　adenophorum　in　the　degraded　tiankeng.