The invention relates to an equivalent simulation method for clamping dual sub-modules. The method is characterized in that a switch device is deemed as a controlled resistor; Thevenin equivalence is conducted to the clamping dual sub-modules; controlled voltage sources and the controlled resistor are used to simulate the clamping dual sub-modules; and different assignment schemes are introduced to conduct equivalent simulation of all the sub-module states of the clamping dual sub-modules under different working conditions. A simulation model established by the method only adopts three controlled voltage sources, one controlled resistor and two diodes; only a few of components and parts are designed; the simulation model is simpler; and simulation efficiency of the simulation model can be increased.