Model-based methods are commonly used for fault diagnosis. Many model-based fault diagnosis approaches have been proposed so far. But for modern complex processes, due to the variable nature of faults and model uncertainty, no single approach can diagnose all faults and meet different contradictory criteria. In this paper, the importance of integration of different fault diagnosis schemes in a common framework is emphasised. A service-oriented architecture for the integration is proposed based on Grid technologies. The preliminary implementation of this integration for the gas turbine engine fault diagnosis is discussed.