Abstract: The effect of light intensity on Rauvolfia yunnanensis was studied under four different light conditions, namely: 1. 100% daylight (shadeless); 2.73% (27% shaded); 3. 48% (52% shaded) ; 4. 28% (72% shaded). The most suitable light intensity required for the growth of plant, both on the plant height and diameter, was varying from 28% daylight (at dry season) to 73% daylight (at foggy season) at different seasons. Under the half shaded condition (48% light intensity), the annual production of roots, leaves and stems was greater than under any other light conditions (100%, 73% or 28% light intensity). The total number of flowers was depressed markedly by shading, but the number of fruits yielded was higher under 73% light intensity. The number of embryoless seeds was as high as 96% under full light condition (100% light intensity), but decreased apparently under the shading of forest canopy. The size of leaves, fruits and seeds was varying quite a bit with different light intensities. Finally, we have to mention that the alkaloid contents in the leaves tended to increase with the decreasing of the light intensity.