Abstract: In order to reduce the fault of foundation brake system of CRH1 EMU effectively, the principle of GO methodology is present to analyze the reliability characteristics of foundation brake system. Based on GO methodology, the model of reliability is established. According to the reliability characteristic quantities such as availability and failure rate of the electrical components and mechanical parts and combine with the logic relationship of air source system operator, obtain the precision formula of failure rate and maintenance rate of repairable system, the reliability characteristic of foundation brake system of EMU is quantificationally calculated with development of the corresponding GO process. The result shows that this method can get all the possible factors and weak links of the foundation brake system failure to provide a theoretical basis on the maintenance and fault diagnosis of air source system.