The dynamic simulation method based on the first principle model is considered to be useful especially when revision of the operation and control on experiences of plant engineers during run of the distillation plant is risky due to unstable behavior, use of unstable substances, complicated structure of the plant and so on. However, in the case of application of a conventional mirror modeling method in the Mirror Plant where the tray efficiency is constant, the simulated temperatures before revising the control method are seen not to agree well with the observed plant data. We propose use of vapor temperatures for estimation of vaporization efficiency for the equilibrium stage models by using the mirror modeling method in the Mirror Plant, which composes three system modes. In the case of adopting a time-variant model for the efficiency, the simulated temperatures before revising the control method are seen to agree well with the observed ones. Then, it was simulated using the correlation model between vaporization efficiency and vapor temperature adjusted for conventional control method whereby the periodical fluctuation can be stabilized after switching to the revised control method. Thus, the revised control method is implemented in the Distributed Control System, and it is observed that fluctuation of the vapor temperature became remarkably small. An application method of the vaporization efficiency based on temperature data is shown by dynamic simulation of remarkable periodical fluctuation of temperatures in a distillation column. Hence, it is made clear that the above-mentioned methodology for mirror modeling is useful and valuable for an improvement and verification of control loops for more stable operation of a plant.