Abstract: The switchgear and its controller are one of the most widely used components in the distribution system and it is necessary to ensure their reliability. This paper proposes a three-dimension coordinated reliability evaluation model for switchgear and its controller. It aims to build a more systematic reliability evaluation of switchgear and its controller from the source of its fault and the spatial structures. In the special dimension, the fault type is divided into many parts according to the location of the switchgear and its controller’s components. And then the defect database which can guide the maintenance of operation and maintenance is established on the basis of space dimension. Meanwhile the reliability evaluation of switchgear and its controller need to consider Failure Modes and Effects Analysis (FMEA) to reduce the maintenance cost. In the source dimension, the qualitative and quantitative reliability analysis of the switchgear and its controller is carried out based on Fault Tree Analysis(FTA). Then the reliability improvement measures based on Product Lifecycle Management is offered. Finally, the proposed method is verified on the vacuum load switch cabinet in Guangzhou, China. The method presented in this paper can effectively improve the efficiency and accuracy of failure analysis for STDS, cut down occurrence of failure and improve the STDS utilization.