从连续介质流体力学的观点，采用局部体积平均方法，建立了一个描述作物覆盖条件下土壤热湿迁移过程的二维数学模型．以能量平衡原理及土壤层水汽扩散理论为基础，建立了根系吸水吸热、作物蒸腾和土面蒸发模型．两者耦合适用于求解ＨＩＰＡＳ系统中热湿传输问题． From the perspective of continuum fluid mechanics, a two-dimensional mathematical model describing soil heat and moisture migration under crop cover was established using the local volume-average method. Based on the theory of energy balance and diffusion theory of soil water vapor, models of root endothermic water absorption, crop transpiration and soil evaporation were established. The coupling between the two is suitable for solving the problem of heat and moisture transfer in HIPAS system.