Abstract: The leaf characteristics of hybrid corn (yuedin 9) for different planting densities were tested in the experimental farm of South China Agricultural University in Guangzhou China in the spring of 1996. The corn yield characteristics were better in the density of 45 thousand plants per hectare than in the density of 67 5 thousand plants, but that was not reach a singificant level. The total leaf age of the tested hybrid corn was 19.1 and also was a rather stable character. The relationship between the leaf area and the dry matter inerement showed index cure. The plants of low density, population had higher assimilation rate in the late growing stage. The long wide rate of leaf showed parabola cure. The longest and widest leaf was 12th leaf and 13th leaf, which were unfolded at the young panicle differentiation stage. Every other leaf appeared in 3 days and unfolded in 2 days in the middle and late growth period, but senecensed in 5 to 10 days. The function days of leaves would extend with leaf arrangement.