Broadcasting is the most basic manner to transmit messages in mobile wireless sensor networks. However, existing relevant broadcasting algorithms in mobile wireless sensor networks need a large number of intermediate forwarding nodes. The large number of intermediate forwarding nodes causes a mass of redundant message packages. Massive redundant messages will consume much energy and lead to a short life period of mobile wireless sensor networks. This paper proposes a broadcasting algorithm named node density and distance-based probability (NDDP for short). The average forwarding ratio of the algorithm is only 5S/(Nπr2), where S is the area of the networks, N is the amount of nodes in the networks, and r is communication range. Then the average receipt ratio of NDDP is more than 95 percent in theoretical analysis and more than 92 percent in the ns-2 simulation results. Denser the network is, the more energy saving the algorithm is. Simulation results also show that NDDP outperforms the two algorithms in Smite and Sidewinder not only on the aspect of stability but also on energy conservation.