In this study, we investigated the drying characteristics for pulp sheet at different hot air temperature (80, 90, and 100℃). The drying kinetics were modeled using one- to five-term solutions of Fick’s second law of diffusion at different drying conditions. It was found that these models underestimated the initial drying stages and overestimated the final drying stages. Meanwhile, the values of the diffusion coefficient tended to stabilize when the series terms more than three. In order to improve the accuracy of the mathematical models, the modified one- to three-term models were also used to describe the drying kinetics. The results showed that modeling data was agreed with the experiment data better than the series solution models based on Fick’s second law of diffusion. Besides, the accuracy improved dramatically as the terms of the model increased. The minimum diffusion coefficient was 0.996 for the modified three-term model. It was concluded that the modified model could simulate the pulp sheet drying process under the conditions studied.