Intramolecular dynamics of HOD was investigated by the classical trajectory method and detailed mechanisms of vibrational energy exchange were studied. The time evolution of mode energies in each vibrational mode along the trajectories was calculated. A periodic energy exchange, that is, a vibrational recurrence between the bending and OD stretching modes, is observed. The centrifugal force by the angular bending motion and the coriolis force due to stretching of the OD bond undergoing angular motion are responsible for the recurrence. Implication of the present finding in intramolecular vibrational relaxation and mode selective chemistry is discussed.