Abstract: The light-photosynthesis and the ecophysiology responese of various kinds of keny typical rice (Oryza sativa subap. Keng Ting) at different altitudes to light and temperature were investigated under field culture and pot culture conditions. The five varieties of keny rice were used. Keng No. 10, Dao No 4, Mei Dan,79-2 and Chu Keng No. 3 altitudes of 2510, 2490, 2400, 2200 and 1850m, respectively. The results indicated all photosynthetic characteristics of keny rice varieties at different altitudes showed apparent gradient variations. Under lower intensity of illumination, the photosynthetic rate at the ear-bearing stage would gradually decrease in Keng rice varieties along with the increase in altitude. Under higher intensity of illumination, however, the rate would gradually increase along with the increase in altitude. The relationships between photosynthesis of Keng rice and illumination could be determined by the curve equations: p=a+blgI, where p is photosynthetic rate, I is light intensity. The light saturation point of keng rice showed a tendency to increase with the rise of altitude. The effects of shading on yield parameters of keng rice at bighter altitudes were much greater than of keng rice at lower altitudes. The plateau keng rice varieties have high coldtolerance when different varieties exposed to low temperature at the blooming stage. The results suggested that different photosynthetic ecophysiology responses to light-temperature were determined by their difference in matabolic pattern and adaptability to the environment.