In order to improve the material properties of Populus tomentosa, and increase its utilization rate for furniture products. Two modification methods, including freezing and steam treatments were adopted in this work, and special attention was given to the permeability of Populus tomentosa with respects of processing time, temperature and moisture content. According to the experimental results, the optimum modification parameters for Populus tomentosa with freezing treatment are processing temperature of ‐20 °C, time of 2 hours and saturated moisture content; while the optimal modification parameters with steam treatment are as follows: processing temperature of 120 °C, time of 2 hours and saturated moisture content. Based on comparing the weight gain rate at different processing condition, steam treatment has greater influence on the permeability than that of freezing treatment. In general, steam treatment was proposed to be used in the property modification of Populus tomentosa in terms of greater permeability.