Software architecture has the potential to provide a foundation for dynamic software evolution．In this paper,based on a specific software architectural style，the dynamic evolut ion mechanism for distributed system are studied and put into practice．Firstly software architectural style named JB/HMB is described based on hierarchical message bus．Then the dynamic evolution types and processes，which are supported by JB/HMB，are dis cussed， Finally, ZIS，an implementation of hierarchical message bus，is proposed to support dynamic evolution of distributed system adhered to JB/HMB．