This article indicate that high grain yicld of maize were given by satisfactory piant density (in certain iocation) .The higher density with larger range of suitable plant densities were allowed at rich soil, and lower density with smaller range at poor soil.Increasing plant density over the max.limit of suitable density slowed down leaf elongation, delayed silking, increased the percentage of defective kernels and decreased floweret number/ear, then plant development were restrained.These were caused by weakly light at the high fertilizer condition and by the lackness of fertilizer on the poor soil.
In the light of these experimental results, the mid or lower suitable plant density for the high yield of maize in large area should be selected.