Abstract: Based on the brief description of the feature and characterizations of ecosystem,this work mainly concludes the ecosystem as a typical selforganized structure system,with nonequilibrium and dissipated/dispatched features.The work explained the concepts of ordered,disordered and chaos status of ecosystems and distinguishes the differences among related gradual change,mutation and forking in evolution of the system.The paper elaborates the features of selforganizing and procedure of emergence of new species and introduces entropy as a trait to assess/evaluate the biodiversities in the system:biodiversity becomes complicated and abundance as the value of entropy increases,vice versa,biodiversity becomes simple and few as the value of entropy decreases.This paper also approaches the relations between biodiversities and stabilities of ecosystem and concludes that there is no natural link between biodiversity and stability in the ecosystem.