Abstract: ObjectiveSymbiotic effects of ericoid mycorrhizal fungi inoculation on Rhododendron moulmainense were analyzed to provide reference for growing seedling with mycorrhizae.MethodBig seedlings(b,1.5 years),middle seedlings(m,1.0 year)and small seedlings(s,0.5 year)of R. moulmainense were set. Arti-ficial inoculation experiment was applied to analyze effects of Phialocephala fortinii(Pf)and Aspergillus sydowii(As)inoculation on seedling growth, root system characteristics and chlorophyll fluorescence parameters of R. moulmainense.ResultSeedling growth of big and middle seedlings inoculated with Pf and As were promoted compared with non-inoculated seedlings(CK). The promo-tion effects of As on above ground and underground parts of big and middle seedlings were smaller than As. Pf inoculation had the optimal promotion effects on above ground part of middle seedlings,and followed by the effects on above ground part of big seedlings. Root growth improvement of big seedlings inoculated with Pf was the most obvious,that of middle seedlings was the second. However,Pf and As inoculation presented inhibition effects on above ground part and root of small seedlings. Specific leaf areas of inoculated seedlings were lower than that of CK. Yield of light quantum(YII),non-photochemical quenching(NPQ),electron transferring rate(ETR)of inoculated seedlings were significantly higher than those of CK(P<0.05),and their multiples of ascension compared with CK were:small seedlings>middle seedlings>big seedlings. As a whole,photosynthetic ability of seedlings inoculated with Pf was higher than those inoculated with As.ConclusionAfter inoculation,big,middle and small seedlings can form good symbiosis with Pf and As. Photosynthetic ability,plant and root growth of big and middle seedlings inoculated with Pf and As are promoted,and the effects of Pf are more obvious. But growth of small seedlings inoculated with Pf and As is inhibited. Therefore,Pf inoculation applying to middle seedlings is recommended for growing seedling with mycorrhizae.