Abstract: The effects of light intensity, mineral nutrients and seasonal climatic changes on the alkaloid contents of Rauvolfia yunnanensis Tsiang were studied and the experimental results were summarized as follows: The alkaloid contents of Rauvolfia roots increased with the light intensity decreased, and a maximum was reached at about 28% of the normal day light. The supply of the mineral nutrients of P, K especially N would raise the root production and alkaloid contents respectively. Determinations were carried out about the variations of alkaloid contents of the roots, stems and leaves on the samples collected every month of the year from both the wild and the cultivated Rauvolfia. The alkaloid contents in the roots of both wild and cultivated Rauvolfia appeared with only one high peak-August to September (end of the raining season), and a period with low contents appeared from March to May (dry season). The alkaloid contents in stems appeared with two high peaks, one was in coincidence with that of the roots, the other appeared between March and May (dry season) just as the period with low alkaloid contents in root. The alkaloid contents of leaves of wild Rauvolfia appeared with two high peaks, both were the same as those of the stems, but in the cultivated Rauvolfia, only one peak with high contents from July to August (raining season) was observed.