Abstract: The gradient production and gust ejection of turbulent transfer have been combined to develop a first-order closure model for simulating plant canopy micrometeorology and the above environment with reasonable consideration to the transitional layer above the canopy. The model simulates the vertical distributions of air temperature, specific humidity, and wind speed within and above a tea canopy very well. Objective and reliable values of the parameters involved in the model were computed with nonlinear multidimensional approach alaorithm employed from optimizing theory and method.All the mechanisms and processes in momentum and water and heat exchange between vegetation canopy and the atmosphere are different that is mainly owing to the adjustment. adaptation. and feedback of the plant to the variation of its environment. It is gradient production rather than gust ejection that causes water vapour and heat to move within a short dense plant canopy. while for momentum transfer. both of them are equally important. especially in the lower part of the canopy.