The visualization modeling of maize canopy structure was studied in this paper. Two maize sample plots with different planting density were selected in the field, and four maize plants in each plot were studied. The spatial coordinates of five characteristic points along the coastal line of each maize leaf were determined in situ . A general quadratic equation was proposed to characterize the curvature of maize leaf, and the coefficients of the equation were determined by the method of least square regression based on the observed data, then the structure of maize leaf was modeled by using the computer. The results of visualization modeling of maize leaf structure were consistent with the actual situation of maize grown in the field.