Abstract: 【Objective】 It is a new tendency to obtained some vigorous citrus seedlings and improve fruit quality by the way of mycorrhizal citrus seedlings. After a series reasourches of mycorrhizal trifoliate seedlings (Poncirus trifoliata), this experiment try to select a better dominant species (isolate) of AM fungi for an inoculum of trifoliate orange seedling.【Method】Pot experiment was conducted to study the effects of AM fungi Gigaspora margarita，Glomus mosseae and Glomus versiforme on the vegetative growth and mineral contents of trifoliate seedlings, and the inoculation effects were compared among the three species.【Result】 The roots of seedlings can be colonized effectively by AM fungi. Compared with the control, Inoculation could promote the vegetative growth including the shoots and roots. The improving effected on the root system was significant, especially on the fibrous root. Inoculation with AM fungi also significantly increased the levels of N, P, K, Ca, Mg, Zn, Cu and Mn in seedling leaves. The effect of three species of AM fungi decreased in the following order: Glomus mosseae, Gigaspora margarita and Glomus versiforme. But the mineral contents of leaves did not go all the way with the trend of growth.【Conclusion】The inoculation effects of Glomus mosseae among the three AM fungi on the seedlings were best in the vigorous vegetative growth, minaeral absorbability example for N, P, Mg and Cu. Yet the dependency of trifoliate orange seedlings to G.mosseae was strongest compared with the other two species of AM fungi. So, the species of G.mosseae is the best fitting inoculum for mycorrhizal trifoliate orange seedlings among the three AM fungi in this experiment.