Endophytic　bacteria　residing　within　host　plants　can　significantly　impact　on　the　host＇s　growth,　health,　and　overall　relationship　with　its　surrounding　environment.　However,　the　process　that　shape　the　community　assembly　of　stem　bacterial　endophytes　(SBEs)　remains　poorly　understood.　This　study　explored　the　community　structure,　cooccurrence　patterns,　and　ecological　processes　of　the　SBEs　inhabiting　the　shrub　host,　Mussaenda　pubescens,　across　seven　locations　in　southeastern　China.　We　found　that　the　absolute　abundances,　alpha　diversity,　and　community　composition　of　SBE　communities　exhibited　notable　differences　among　various　host　populations.　Stem　chemical　characteristics　were　the　most　important　factors　influencing　SBE　community　distribution,　followed　by　geographic　distance　and　climatic　factors.　The　beta　diversity　decomposition　analyses　indicated　that　SBE　community　dissimilarities　between　sites　were　nearly　equally　driven　by　similarity,　replacement　diversity,　and　richness　difference.　The　co-occurrence　network　analysis　revealed　that　the　keystone　taxa　were　mostly　observed　in　rare　species,　which　may　be　essential　for　preserving　the　ecosystem＇s　functions.　Conditionally　abundant　taxa　(CAT)　showcased　the　highest　closeness　centrality,　while　exhibiting　the　lowest　degree　centrality　and　betweenness　centrality　as　opposed　to　rare　taxa.　In　addition,　stochastic　processes　also　played　an　important　role　in　structuring　SBE　communities,　with　ecological　drift　being　the　dominant　factor　for　both　abundant　and　rare　taxa.　This　study　would　deepen　our　understanding　of　the　ecological　dynamics　and　microbial　interactions　within　plant　endophytic　microbiomes.