Contradiction between the global QoS requirements and local service QoS status monitor decreases the availability of composite service

and makes it hard to meet users' requirements.Aiming at this problem

a framework for composite service adaption is proposed.And the mechanism for composite services QoS decomposing and individual service status monitor in this framework is demonstrated.To get the threshold of individual service

an approach to predict the service QoS by analyzing the historical QoS is studied.Further

to decrease the overhead of composite service adaption

the relax index is introduced into the mechanism.The experimental results show that predicting the QoS threshold and relax index can make the composite service QoS decomposing more reasonable

and can satisfy the user's end-to-end requirement through little adjustment to the greatest extent when changes happen.