Sorption isotherms of pea seed were determined experimentally by using a static gravimetric at temperature of 30℃, 40℃ and 50℃ and within the water activity (aw) range of 0.11~0.92. Four mathematical models were determined by using non-linear regression method. The results showed that equilibrium moisture content (EMC) was decreased as the increase of temperature, and the GAB model fitted well the isotherms data of pea seeds and was considered as the best model for predicting seed moisture. The thermodynamic properties involving in net isosteric heat, differential entropy, enthalpy-entropy compensation, spreading pressure, net integral enthalpy and net integral entropy were analyzed systematically for further understanding of water sorption mechanism. The net isosteric heat and differential entropy were obviously decreased with the increase of EMC, which satisfied the compensation theory. The data indicated that moisture sorption of pea seed was non-spontaneous and enthalpy-controlled processes. And the net isosteric heat approached to the latent heat of pure water around 25% (dry basis). The expansion pressure of seed sorption process was decreased with the increase of temperature at given aw and increased with the increase of aw at a given temperature. When expansion pressure was at fixed level, the net integral enthalpy was decreased with the increase of EMC, while the net integral entropy was decreased with the increase of EMC to a minimum value of -137.79J/(mol·K), -140.29J/(mol·K) and -137.74J/(mol·K) at 30℃, 40℃ and 50℃, respectively, and then tended to increasing trends. The aw (0.017, 0.045 and 0.062) and EMC (2.7%, 2.5% and 2.4%), which resulted in the minimum net integral entropy values at the temperatures of 30℃, 35℃ and 40℃, respectively, can be considered as the maximum stability storage conditions of pea seed.