Abstract: To address the issue of uneven temperature distribution in vacuum drying furnaces affecting material drying uniformity, a parameter optimization method based on multiphysics coupled simulation is proposed. First, a three-dimensional heat transfer model of the furnace chamber is established by integrating solid and fluid heat transfer, fluid flow, and radiative heat transfer mechanisms. The results show good agreement between simulation and experimental data, with an average absolute error of 1.11℃ and an average relative error of 2.12% for 36 temperature measurement points. Based on the validated model, the effects of chamber pressure, zoned heating-film power density, and intermediate aluminum plate thickness on temperature uniformity were investigated. The results indicate that temperature uniformity improves initially and then tends to stabilize as pressure decreases, particularly around 1/8 atm. Under atmospheric pressure, a 10% increase in edge power density relative to the central region provides better temperature uniformity. Increasing the thickness of the intermediate aluminum plate reduces the temperature range but also lowers the average temperature. A thickness of 18–20 mm yields favorable overall temperature distribution characteristics. The results provide a reference for thermal field optimization and structural design of multi-layer plate vacuum drying furnaces.