Abstract: 【Objective】To reveal growth promoting functions of three Trichoderma species in Paeonia delavayi rhizosphere,and to discuss their effects on growth and development of seedlings,so as to provide statistical support and reference for the resources utilization of rhizosphere Trichoderma and the quality improvement of P. delavayi.【Method】Rhizosphere fungi,Trichoderma koningii,T. paraviridescens and T. harzianum,were used to determine the indoleacetic acid(IAA)producing ability,siderophore-producing ability,phosphorus-dissolving and potassium-solubilizing activity. Effects of inoculated and uninoculated target strains on growth,biomass,chlorophyll content and resistance-related physiological indicators of P. delavayi seedlings were discussed,and the membership function value method was used to comprehensively evaluate the plant quality.【Result】T. harzianum and T. koningii had IAA producing ability,of which T. harzianum had the stronger ability. Only T. koningii had the ability to produce siderophore,and the iron content of P. delavayi seedlings inoculated with T. koningii was 3-5 times higher than that of other treatments. The three Trichoderma species had no ability of dissolving phosphorus,while the soil and root acid phosphatase activity of plants inoculated with T. paraviridescens were significantly higher than those of the other treatments(P<0.05,the same below). Only T. harzianum had the potassium-solubilizing activity,and content of soil available potassium and plant total potassium after inoculation were the highest. Furthermore,plant height and leaf increments of P. delavayi seedlings inoculated with T. paraviridescens were the highest,which were 3.23 cm and 3.70 pieces,respectively. The stem diameter was the thickest. Meanwhile,the chlorophyll content,superoxide dismutase(SOD)activities in leaves and roots and catalase(CAT)activity in roots were the highest. The content of soluble sugar(SS)in leaves inoculated with T. koningii and that of soluble protein(SP)in leaves inoculated with T. harzianum were significantly higher than those in the other treatments. The content of SS and SP of roots inoculated with Trichoderma spp. were significantly higher than those of control. Considering principal component analysis and membership function value,the seedling quality in different treatments was comprehensively scored,from high to low,as follows: inoculation with T. paraviridescens treatment>inoculation with T. harzianum treatment>inoculation with T. koningii treatment>uninoculated treatment.【Conculsion】Inoculation of the three Trichoderma species in rhizosphere has positive effects on nutrient absorption,photosynthesis and resistance induction of P. delavayi seedlings.Growth traits,chlorophyll content and antioxidant enzyme activity of seedling treated with T. paraviridescens are improved significantly,which is an ideal growth promoting fungus for P. delavayi.