Abstract: Background and Objective: Hyacinth, one of world-famous bulbous ornamental plants is widely planted in various habitats. The present work tried to evaluate whether and how inoculation with arbuscular mycorrhizal fungi (AMF) regulates flower morphology and flowering duration of hyacinth. Materials and Methods: Three AMF species, namely, Diversispora spurca (D. spurca), Diversispora versiformis (D. versiformis ) and Funneliformis mosseae (F. mosseae ) were inoculated into potted hyacinth (Hyacinths orientalis L. Anna Marie) plants for 130 days. Flower morphology, flowering duration, nutrient status, indole acetic acid (IAA), chlorophyll and anthocyanin concentration were measured. Data were analyzed by one-way analysis of variance (ANOVA) with SAS. Significances of treatments were compared by the Duncan’s multiple range tests at p<0.05. Results: Root mycorrhizal colonization varied from 38.0-48.7%. Amongst three AMF species, only F. mosseae significantly (p<0.05) has increased flower biomass, opening flower number, flower stem height and floret diameter. Diversispora spurca and F. mosseae, respectively prolonged flower duration for 1.4 and 3.3 days. Mycorrhizal plants with F. mosseae had significantly (p<0.05) higher IAA concentration of flowers and roots, higher anthocyanin concentration of flowers, higher chlorophyll b and total chlorophyll levels of leaves and greater N, P and K levels of flowers and roots. Diversispora spurca colonized plants possessed significantly (p<0.05) higher flower IAA levels and leaf chlorophyll b and total chlorophyll concentrations. Diversispora versiformis generally did not affect these variables. Conclusion: Mycorrhizas could modulate morphology, color and duration of flowers in hyacinth, which is closely related with nutrient status, IAA levels and AMF species. Meanwhile, F. mosseae exhibited the best stimulated effects and can consider to be used in hyacinth cultivation.