As a new type of green and low-carbon biomass composite material, ultra-thin fiberboard has received great attention in the market. However, due to the complexity of the hot pressing process, it's not easy to quantitatively analyze the influence of hot pressing parameters on the properties of ultra-thin fiberboard. This study investigated the relationship between the temperature and time of hot pressing and the physical and mechanical properties of fiberboard through the mechanism of moisture transfer. A mathematical model for temperature, time, and moisture content was established, as well as a neural network prediction model for the influence of moisture content on the physical and mechanical properties of the board. An ultra-thin fiberboard heat and mass transfer model was built by researching the heat and moisture transport mechanism. Fluent software simulation was used to determine the moisture content of the boards under the matching hot pressing process. This study helps to optimize the hot pressing process and improve the product quality and production efficiency of ultra-thin fiberboard.