Abstract: Four different varities of rice including Jingyou527，Changmi011，Jiuyou418 and Hexi39 were used as materials to carry out field experiment in Xichang and Ya'an in order to study the effects of planting density on rice LAI and grain-to-leaf ratio after full heading stage under the two different ecological conditions. The results showed that，rice LAI at different growth stages increased with the increase of planting density，rice LAI of the four varieties in Xichang were significantly higher than that in Ya'an before the booting stage，rice LAI of three varieties（except for Changmi011）in Ya'an were significantly higher than that in Xichang after booting stage. Grain-to-leaf ratio had the trend of increase in high density planting，and that in Xichang was larger than that in Ya'an from 10 days after full heading stage to maturity stage.