It is inconvenient to analyze the actual efficiency of the traditional three-phase triple circuit. Based on the operation state of three-phase triple circuit in non-ideal state, the equivalent model of components in non-ideal state is deduced, and the equivalent circuit of non-ideal system is established. According to the equivalent circuit, the calculation formula of efficiency is deduced and the duty cycle and the ultimate influence of component parameters on efficiency are analyzed in the non-ideal state. It provides theoretical basis for system analysis and device selection and parameter calculation in circuit design. The SEMISEL loss simulation and Matlab circuit simulation are carried out, and the experimental prototype is built. The simulation and experimental results coincide with the derived models, which verifies that the derived model can well describe the influence of different factors on efficiency under non-ideal conditions. This work is supported by National Natural Science Foundation of China (No.61304115).