To address the issue of overlooking the non-uniform distribution of parameters among submodules in traditional multiphysics field modeling of PP-IGBT devices, a novel multiphysics field coupling model is proposed, which incorporates the stochastic distribution of pressure and conductivity among submodules. Firstly, a mathematical model for the pressure distribution of submodule groups and the conductivity distribution of chips using mathematical statistics methods tailored to PP-IGBT devices is established. Next, an electrical-thermal-mechanical multiphysical field coupling model for multi-chip PP-IGBT devices is constructed, validated through single-chip transient experiments. Lastly, a stochastic simulation method is introduced, based on the Monte Carlo method to address the variability in pressure and conductivity among chips. Besides, statistical analysis under conditions of uneven parameter distributions among submodule groups is conducted, elucidating the current and temperature distribution laws in such scenarios. Results show that the uneven pressure and conductivity of the single-chip submodule have a great impact on the distribution uniformity of the current and temperature, with a maximum increase in the unevenness of the electro-thermal distribution about 390% and 19%, respectively.