Due to the scarcity of spectrum resources, the millimeter wave bands have been considered for 5G New Radio. Highly directional and multiple beams are used to overcome the isotropic path loss in mmWave cellular systems. Therefore, the synchronization signals should include more additional information, such as the synchronization signal block index and the beam resource index. In this paper, an efficient sequence of tertiary synchronization signal is designed, carrying the SS block ID and the beam ID. And a joint detection scheme is proposed, to reduce the complexity of detection in synchronization. Finally, simulation results show that the proposed scheme can provide robust capabilities and good performance, which contributes to the standardization of 5G.