In order to detect open-circuit fault in rectifier stage, a fault diagnosis method applied to indirect matrix converter (IMC) is proposed in this paper. Firstly, the theory and feature of space vector modulation (SVM) are introduced. Then, detailed circuit analysis of IMC under fault condition is fully studied, and from the view of energy transfer, the influence of open-circuit fault on output voltage is analysed. Based on the circuit analysis, this paper presents a fault diagnosis technology to detect and locate faulty switch by combining the corresponding relationship between the rectifier stage sector and bidirectional switch. The proposed method has the advantages of being easy to understand, locating faulty switch accurately, requiring no additional sensor in dc-link side. Simulation results are presented to verify the proposed fault detection technology.