Nowadays, Mycorrhiza fungi are widely used due to their ability to have symbiosis with the roots of so many plants. The role played by these fungi in supplying some of the nutritional demands and water required by the plants is now certain. This research studies the effect of the symbiosis of these microorganisms on corn and applying them simultaneously with phosphorous chemical fertilizers under different levels of irrigation. The interactions effect of these factors have also been studied that not only revealed the effect of such symbiosis between the above said fungi and corn, but also, identified phosphorous chemical fertilizer as the best fertilizing compounds.The results indicated that the effect of Mycorrhiza fungus to had a significant. On the characteristics under the study, however, such efficiency revealed a decreasing trend as the use of phosphorous fertilizers increased. Moreover, under water stress, the plant status improved when fungi were applied.