A pots experiment was carried out using two soil types (clay loam and sand soil) to study the interaction between VA-mycorrhizal (My) and some soil fungi under the effect of rock phosphat on growth of onion plant. The interaction between mycorrhizal (My) and other soil fungi increased the fresh weight of root in comparison with mycorrhizal (My) alone, however the differences were not significant except for (Saccharomyces+Mycorrhiza) (Sac+My) similar results were obtained in sandy loam soil. The percentage of root colonization on the growth of onion plant was not effected by the interaction between mycorrhiza (My) and other osil fungi (Actinomucor, Aspergillus, Penicillium, Saccharomyces) (Act, Asp, P, Sac). This value, however was high in the second harvest in treatment mycorrhiza (My) and (My+Sac) (My+Act) The VAM- fungus alone and their interaction with other soil fungi increased the plant growth.