The planting density experiment of the elite Dian type(japonic) hybride rice DianZa31 were conducted in two different area .one is in Mouding county where it is in warm japonic rice area , Yunnan, the other is in Dali city where it is in cool-warm japonic rice area , Yunnan. The results show that, in warm japonic rice area ,Dianza31's optimum planting density is 300,000 hills per hm2 and two seedlings per hills; in cool-warm japonic rice area , it's optimum planting density is 450,000 hills per hm2 and two seedling per hill. the difference between the yields of different planting density is significant at 5% level in both experiments.