Abstract: With the application background of reliability evaluation of power electronics devices, a one-dimensional field algorithm was proposed to obtain the online temperature and pressure of press-pack insulated gate bipolar transistors（IGBT） in this paper. The two physical fields were one-way coupled. The IGBT module branch was simplified into a one-dimensional model through three hypothetical conditions.Based on the heat transfer equations, frequency domain analysis and mechanical equations, the theory of the proposed method was discussed. In the meantime, the proposed method was revised considering the heat dissipation condition of the IGBT module, heat flux diffusion and pressure edge effect.Finally, the results of this method and finite element method were compared taking the six chip IGBT module as an example.The results show that the online temperature and pressure of press-pack IGBT can be calculated accurately with the proposed method. The proposed method significantly shortens the calculation time while ensuring the calculation accuracy compared with the finite element method. Compared with the one-dimensional thermal network method, it is not necessary to iterate repeatedly when calculating the two-way coupled multiple physical fields.