Abstract: Broadcasting is a common operation in ad hoc wireless networks with severe resource constraints.The problem of broadcasting storm aggravated the resource consumption in ad hoc networks.We propose energy efficient broadcasting strategy without collision for ad hoc networks which is made use of 2-hop neighbor knowledge,the surplus energy of a node and the degree of node to decide to rebroadcast.The nodes in forward node list are divided into several independent subsets which can rebroadcast simultaneously without collision.The different time of rebroadcast is set adaptively by the density of independent subset node.Analyses and simulations have shown that the strategy has prolonged the lifetime of network,had fewer redundant rebroadcast,higher reachability and lower delay than other algorithms.