RC5 receives a wide range of favor and support in security protocols of low-speed wireless networks (LSWN). In order to further study whether RC5 applies to LSWN, this paper simulates two kinds of LSWN model that includes RC5 algorithm and without RC5 algorithm through the OMNeT++ simulator. By comparing the performance of the two kinds of LSWN model, such as End-to-End Delay of the packet, Packet Loss Rate of the node, the experimental statistics prove that introducing RC5 only brings a little overhead into the whole network. Therefore, we consider that RC5 is fit to LSWN to provide security communication.