To study the effects of shading on photosynthetic physiology and chlorophyll fluorescence of Pinellia ternata.Plant growth, chlorophyll content, net photosynthetic rate (P(n)) and chlorophyll fluorescence in P. ternata were investigated under different shading treatments (0%, 70% and 90%) when it grew about 15 cm high.The results showed that fresh weight of a tuber, height, leaf length, width, leaf area, specific leaf area (SLA) and contents of chlorophyll content were enhanced after shaded, and chlorophyll a/b rate declined. Compared with control, net photosynthetic rate, light compensation point (LCP) and light saturation point (LSP) of P. ternata decreased after shading, but apparent quantum yield (AQY) increased; quantum yield of PS II (PhiPS II), minimal fluorescence (F(o)), maximal fluorescence (F(m)), intrinsic photochemical efficiency of PS II (F(v)/F(m)) and photochemical quenching coefficient (qP) were enhanced.Compared with control, all data indicated that there were distinctive differences between the height, SLA, chlorophyll content, P(n) and chlorophyll fluorescence characteristics under the shading treatments (70% and 90%), the fresh weight of a tuber increased after 70% shading, and provided better environmental conditions for the growth of P. ternata.