This paper focuse on the software architecture of the network-based Hall for Workshop of Metasynthetic Engineering. A nested client/agent/server computing scheme-incorporated Requester- Mediator-Provider model is deployed. The framework and its working mechanism of an HWME (hall for workshop of metasynthetic engineering) for macroeconomic decision-making through Java-based intelligent information agents on the basis of above scheme are discussed. Combinations of mobility of agents and message-passing mechan,algorithm and interaction,multiple types of agent technoogy and multiple design patterns are flexiby used in this system.Co,pared with the othe client/server and the browser/server computing schenmes,this system is more flexible,and has less response time and lower requirement for network perfomance.