AbstractThe quality of Dendrobium officinale Kimura et Migo in cultivation was worse than those collected in wild, this work was conducted to explore a method that can improve the quality of D. officinale in cultivation. Seedlings were sprayed with different concentrations of SA with UV-B irradiation (15.6 µW/cm2) for 4 h per day. After 8 days, partial growth indicators and active ingredients in the seedlings were determined. The results showed that UV-B irradiation alone could increase the contents of malondialdehyde (MDA), total polysaccharides, total alkaloids and total flavonoids as well as the activities of antioxidant enzymes, and decrease the contents of chlorophyll in D. officinale. Moreover, UV-B irradiation combined with SA could significantly increase the contents of total polysaccharides, total flavonoids, and chlorophyll as well as the activities of antioxidant enzymes, and decreased the contents of MDA and total alkaloids of D. officinale, when compared with UV-B alone. Importantly, the growth and main active ingredients of D. officinale were enhanced when the seedlings were treated with various concentrations (1.0–3.0 mM) of SA and grown under intense UV-B irradiation. At the optimal concentration (2.5 mM) of SA, the content of polysaccharides was further increased by 27.82%, while the content of MDA was decreased by 43.51%, when compared with UV-B alone. This study provides an insight for improving the quality of D. officinale bionic cultivated in its habitat, which might promote its industrialization.