To study the effect of precipitation on Scutellaria baicalensis and define the suitable water condition for the growth of Scutellaria baicalensis. The water supply experiment was done for 4 treatments which simulate growing seasonal rainfall of Scutellaria baicalensis. Morphological indicators and dry matter weight of each organ were determined; and calculated the ratio of dry matter of each organ in total biomass of Scutellaria baicalensis. The results indicated that root dry weight, shoot dry weight and total biomass of Scutellaria baicalensis dealing with more and fewer amount of water were lower. Insufficient water supply had greater effects on shoot than on roots. Root dry weight, shoot dry weight and total biomass of Scutellaria baicalensis were higher under slight and moderate drought stress. Scutellaria baicalensis was better in drought resistance, The growth of shoot and roots was harmonious, matter distribution of each organ was reasonable and the output was high in the condition of 321 450 mm of the annual rainfall and 250-350 mm of seasonal rainfall.