Asynchronous mechanism is absolutely necessary in the construction of large scale distributed systems.Although being a popular support platform for distributed applications

CORBA doesn't solve the asynchronous communication mechanism problem very well and this limits its application to some application domains.How to provide asynchronous mechanism in CORBA and provide asynchronous communication support for applications at upper layer have become the research hotspot.This paper presents a CORBA asynchronous messaging model Star-Async.The model supports reply processing

exception handling and asynchronous code generation by means of ReplyHandler object

exception encapsulation object and modification of abstract syntax tree accordingly.We have implemented Star-Async model on StarBus

which is our own distributed object-oriented middleware platform implementation.The implementation results of Star-Async and its initial applicationsshow that Star-Async model provides a reference model for the implementation of asynchronous mechanism in CORBA.