To study the effects of salicylic acid of different concentration (SA) on the growth of Pinellia ternate.SA of different concentration was sprayed to the plant as it grew about 15 cm high. Plant height, total chlorophyll content, activity of SOD, MAD content, photosynthesis speed, intercellular CO2 concentration, the transpiration speed and the leaf temperature were measured after 3 times spray.When 0.5 mmol x L(-1) SA was sprayed, the intercellular CO2 concentration, activity of SOD and photosynthesis speed were increased, while leaf temperature and MDA content were decreased.SA at the concentration of 0.5 mmol x L (-1) was suitable for the growth of P. ternate. It obviously decreased sprout tumble and increased the fresh weight of tuber and the alkaloid content.