Intestinal bacteria communities play a pivotal role in promoting host health,thus the disruption of intestinal bacterial homeostasis could result in disease.However,how the intestinal bacterial assembly is affected by the occurrences of disease remain unclear.To address this,we compared the multi-faceted ecological differences in maintaining intestinal bacterial assembly between healthy and diseased shrimp.The results show thatthe relative importance of neutral processes decreases when disease occurs.This pattern is further corroborated by theecosphere null model,revealing that the bacterial assembly of diseased samples iscontrolled by stochasticity dominated processes.In addition,the occurrence of shrimp disease reduces the complexityand cooperative activities of species-to-species interaction.The keystone taxa affiliated with Alphaproteobacteria and Actinobacteria in healthy shrimp shift to Gammaproteobacteria species in diseased shrimp.Changes in intestinal bacterial communities significantly alter biological functions.Within a given metabolicpathway,the patternof enrichment or decrease between healthy and deceased shrimp is coincident with its knownfunctions.Collectively,we propose that the stressful shrimp are more prone to be invaded by alien species(e.g.,more stochastic assembly and higher migration rate),which,in turn,disrupts the cooperativeactivity among resident species.These findings greatly aid our understanding of the underlying mechanisms that govern shrimp intestinal community assembly over the course of health status.