Abstract: The use of IEEE 802.16j of multihop relay (MR) technology was discussed to improve the throughput between the vehicular subscriber station (SS) and the Internet base station (BS) in the vehicular network. In the case that the position of SS and BS are known, by selecting the optimal relay stations, the throughput between SS and BS can be maximized. By incorporating a highway mobility model, with the help of a nonlinear optimization method, the location of the optimal relay which obtained max throughput was ascertained. Finally, the effectiveness of this algorithm was verified through NS-2 simulation experiments, the results showed that comparing the cases without relay, this program increases the expected value of the end to end throughput.