We study the effect of continuous soil natural drought on the growth, physiological indexes of stress tolerance and the contents of main medicinal components of Uncaria rhynchophylla seedlings by pot experiment of soil water control for 12 days. The results showed that: (1) with the extension of drought stress time, the biomass of roots, stems and leaves and the relative water content(RWC) of leaves decreased significantly (P < 0.05), while the content of MDA and the relative electrical conductivity(REC) increased gradually. (2) along with the time of drought stress extended, the content of chlorophyll a and chlorophyll b in leaves increased firstly and then decreased. The activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) increased firstly and then decreased. The activity of POD reached the peak first, and the increase of CAT activity was the largest. The contents of proline (Pro), soluble sugar (SS) and soluble protein (SP) in leaves increased gradually, and Pro showed stronger osmotic regulation ability. (3) The contents of rhynchophylline and isorhynchophylline in leaves, main stems and branches of U.rhynchophylla seedlings increased first and then decreased with the extension of drought stress time. The response time in order was leaves, main stems and branches with hooks. The alkaloid content in order was branches with hooks, leaves and main stems from high to low. It was found that the growth of U.rhynchophylla seedlings was affected by the continuous natural drought in the soil, but the plants could improve their water absorption and retention capacity by increasing their antioxidant enzyme activity and accumulation of osmoregulation substances to resist the drought stress effectively. In addition, the 4th ~ 8th day of drought was beneficial to the accumulation of the main medicinal components, rhynchophylline and isorhynchophylline.Generally speaking, when the relative water content of soil was 42% - 53%, U. rhynchophylla had stronger drought resistance and higher contents of rhynchophylline and isorhynchophylline.