Chen, G., Zhang, J., Liu, P. and Dong, S. 2014. An empirical model for changes in the leaf area of maize. Can. J. Plant Sci. 94: 749-757. Accurate predictions of the leaf area index (LAI) are critical for many crop growth simulation models and essential for simulating crop growth and yield. In this paper, we present a new empirical leaf area model that simulates LAI for different maize (Zea mays L.) varieties under different cultivation conditions. Based on leaf morphological development, the model describes the two processes of leaf growth: expansion and senescence. The effect of planting density and nitrogen on LAI was also simulated in the model. A nitrogen sensitivity parameter was used to distinguish the different varieties. The model predictions were compared with field measurements of LAI for four varieties under different conditions. The results showed that the new model can correctly simulate LAI for maize under different cultivation conditions. The sensitivity analyses revealed that the new LAI model was very sensitive to lle (the length of the ear leaf) and VN (fertilizer sensitivity parameters of cultivars). The new model facilitates the simulation of maize leaf growth and senescence at the population level.