To understand the drying and storage behaviors of industrial hemp flower and leaf, their sorption isotherms must be determined. This study aims to determine the moisture sorption isotherms, fitting mathematical models, and predicting the shelf-life of samples with different mass ratios of powdered hemp flower/leaf at different temperatures. The sorption isotherms of powdered hemp flower to leaf ratios (1:0, 0.75:0.25, 0.5:0.5, 0.25:0.75, 0:1) were determined and shelf-life predicted at different temperatures (20, 30, 40, 50, and 60 °C) using a vapor sorption analyzer; afterward, the adsorption and desorption equilibrium moisture contents (EMC) of different ratios of powdered hemp flower to leaf were modeled using six common empirical models. Both adsorption and desorption EMC of all ratios of powdered hemp flower to leaf decreased as temperature increased. Furthermore, shelf-life of the powdered hemp samples decreases as temperature increases. Modified Halsey and Henderson equations were the best models for the hemp sample isotherms.