By investigating the effects of nodes distribution and broadcasting range of the route request (RREQ) control packets on the routing path establishment, in this paper, we explore the energy efficiency of AODV (Ad-hoc on-demand distance vector) routing algorithms in Ad-Hoc networks. Simulation results show that with the range adaptation to the number of nodes the highest successful rate of routing path establishment is obtained. With the adaptive broadcasting range the routing efficiency can be improved. Thus, the demand transmitting energy of RREQ control packets to establish a routing path can be reduced.