Electro-hydraulic brake (EHB) provides improved braking and stability functions such as ABS, TCS, ESC, EBD, etc. It also removes complex mechanical parts for freedom of design, improves maintenance requirements and reduces unit weight. But, the EHB should be at least as reliable as the conventional hydraulic brake system. In this paper, the model-based fault diagnosis system is developed to monitor the brake status using the analytical redundancy method. The performance of the model-based fault diagnosis system is verified in simulations and demonstrates the effectiveness of the proposed system in various faulty cases.