Abstract: Power electronic transformer (PET) based on multiple active bridge (MAB) has the characteristics of modularity, large scale and high complexity. Compared with other PET topologies based on two-port power modules, it faces greater electromagnetic transient (EMT) accelerated simulation difficulties. In order to improve the simulation efficiency and CPU utilization, this paper proposed a parallel equivalent modelling algorithm suitable for MAB based PET. Using the idea of transformer decoupling method, the serial equivalent models were established. Then, a multi-thread parallel simulation framework was given by taking advantage of the high parallelism of the proposed equivalent models. Furthermore, the parallel algorithm evaluation and influencing factor analysis were conducted. Through simulation verification on PSCAD/EMTDC, the results show that the proposed equivalent models can highly fit the detailed models under various working conditions, and the serial speedup factor can achieve 2~3 orders of magnitude. At the same time, a secondary acceleration of 2~3 times can be realized through the parallel equivalent models with reasonable number of parallel threads.