Effective fault diagnosis of electrical control systems enhances both economic benefits and operator safety. However, the complexity of electro-hydraulic control systems, which consist of multiple components, poses a significant challenge for concurrent fault diagnosis. To identify faults with similar features accurately, A fault diagnosis method based on multi model fusion is proposed. OOBNs (object-oriented Bayesian networks) is used to establish the sub-models. The D-S evidence theory is used to establish the concurrent fault diagnosis and reasoning model. A hydraulic control system with multiple branches for subsea blowout preventers is used to study this method. The results shows that the method is effective in the fault diagnosis of faults with similar features.