A comparison and comprehensive verification, including theoretical verification, inter-model verification and experimental verification, was performed on two models, the Künzel model and the Liu & Chen model for the hygrothermal simulation of porous building envelopes, which are driven by relative humidity. The simulations were also carried out by two computation tools, self-programmed Fortran code and COMSOL Multiphysics for the two models. The simulation results were compared with analytical solutions, simulation solutions of other models and experimental data under single/double-sided controlled boundary conditions. The verification showed that the simulation results of the two models agreed well with the comparison values. Through the comparison between the simulation results of the two models, it was found that the two models have slight difference in the low relative humidity section in the hygroscopic range; while in the end of the hygroscopic range (relative humidity gradually increases to nearly 95%), the Künzel model was no longer able to accurately simulate the distributions of moisture. The investigations in this study demonstrate that the two models are fully validated within the hygroscopic range and provide references for the verification of future hygrothermal models.