In this paper, the classification of plant leaves and the estimation of the quality of tree leaves are analyzed, and the shape of leaves is discussed. Firstly, a leaf classification method based on shape, color, indentation and veined features is proposed. Secondly, in the analysis of the factors affecting leaf morphology, the differences of leaf morphology among different species, the influence of optimal leaf distribution on the same internal leaf morphology, and the relationship between branching structure and leaf morphology were studied. Finally, based on the theory of pipe model, a model for estimating the total dry weight of leaves of a single standing tree is established.