We employed a time-dependent, wavepacket method to study the energy efficacy roles on reactivity of the N+N2 exchange reaction which has two transition states on its potential energy surface. Our study shows that translational energy is the most effective energy form in surmounting the double barriers, while rotational energy is the least effective energy form. These results provide us more insight information on energy requirement in surmounting the energy barriers besides a single transition state on the potential energy surface which is not covered by the Polanyi rules.