The interaction of Klebsiella mytoca NG13/pMC73A with Eucalyptus were studied. The results showed that the root surface and even the inner cortex of Eucalyptus were colonized by K. oxytoca. The K. oxytoca was reisolated from rhizosphere, root surface and inner root of inoculated Eucalyptus. The inoculation with K. oxytoca stimulated the excretion of Eucalyptus root and affected the contents of amino acids, carbohydrates, phytohormones of root exudates. The seedlings of Eucalyptusto to inoculation with K. oxytoca increased growth, total dry matter and N content by 29.81% - 100.40% after 3 months in comparinson to the uninoculated seedlings.