In this paper, we suggest a Synchronized Hello Exchange Mechanism improve IEEE 802.11 DCF-PSM in Mobile Ad-hoc Network. When IEEE 802.11 Power Saving Mode works with AODV, Power Saving Mode would be inefficient. PSM changes its state into a doze state when the node does not have any data to transmit or receive. However, in AODV, a node may determine connectivity by listening for hello packet from the neighbors. In stand-by state, because of the periodical local connectivity information exchange, nodes do not go into doze state, regardless of no data to transmit or receive. The node would dissipate the power staying in awake state. To solve this problem, we propose a Synchronized Hello Exchange Mechanism which makes distributed hello packet exchange synchronize. This proposal improves the performance of IEEE 802.11 PSM in stand-by state.