In order to determine the planting density for high-yield cultivation of rice, Liaoyou 5206 was selected as the test rice variety in this study. Three planting densities: low density（LD）, medium density（MD） and high density（HD） were set to study the effects of them on the photosynthetic characteristics and yield of rice population, so as to control the cultivation density and obtain high yield. The results showed that with the increase of planting density,chlorophyll content, net photosynthetic rate and transpiration rate decreased, leaf area index and intercellular CO₂ concentration increased, stomatal conductance was different in different growth stages. At booting stage, MD had the most efficient photosynthetic characteristics compared with HD and LD treatments. Meanwhile, the cultivated density had no significant influence on the seed setting rate and 1 000-grain weight of rice, but had significant influence on the effective panicle number per unit area and total grain number per panicle, thus significantly affecting the yield. When planting in MD, the yield was the highest when the row spacing was 30 cm × 16.7 cm. In conclusion, appropriate planting density is conducive to the construction of a good rice population, high photosynthetic characteristics and increase yield.