This study was conducted to establish the fundamental of cultivation system in southern warm region of Korea by investigation of variation of yield component and yield under the different planting density, and that was 50, 70, 90 and 110 hills per 3.3㎡. In variations of thickness of culm under the different planting densities there were more thick as decrease in density, and there were fine culm in May 20 transplanting. In Seokwang, the optimum planting density was 90 hills/3.3㎡ in May 20 and June 5 transplanting, but in June 20 and July 5, it was 110 hills/3.3㎡, then in Dongjin, the maximum grain yield was obtained on 90 hills/303㎡ in May 20, June 5, June 20 transplanting, but in July 5 transplanting the highest yield was obtained in the plot of density 110 hills/303㎡. The rate of ripened grains was higher in the high density than that of low density on the late season culture. The degeneration of primary, secondary branches and spikelets was decreased with increase in planting density, and there was more significant tendency in Seokwang than in Dongjin. The no. of panicles per m2 was increased linearly with increase in planting density, and the variation of no. of panicles per m2 according to transplanting periods was greater in Seokwang than in Dongjin.