Abstract: Experiments were conducted on inoculation of Ericoid mycorrhiza (ERM) to 1-year Rhododendron huadingense seedlings in 2016.Determinations were implemented on chlorophyll content and photosynthetic properties under different light intensities of inoculated seedling andcontrol (no inoculation). Results showed that chlorophyll content in inoculated seedlings was higher than that in the control, and chlorophyll a/b waslower under two shading covers and three shading covers, indicating that treated seedlings could better capture and use light energy under low lightcondition. Net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), light using efficiency (LUE) and water using efficiency(WUE) was higher in the inoculated seedlings than that in the control, while intercellular CO2 concentration (Ci) was lower. Pn, Tr and Gs of seedlingsunder one shading layer was the maximum, showing that inoculation could increase capture of light. The apparent quantum yield (AQY) andmaximum net photosynthetic rate (Pnmax) was higher in the inoculated seedlings, while the light saturation point (LSP), light compensation point (LCP)and the dark respiration rate (Rd) was lower. The experiment demonstrated that inoculation of ERM on R. huadingense seedlings could improve theefficiency of photosynthesis and reduce Rd under moderate light intensity.