The cell-search procedure in the long-term evolution (LTE) downlink includes the time synchronization, the frequency synchronization of frames, and the acquisition of cell identity (ID). This paper presents a low-complexity detection algorithm for a secondary synchronization channel (S-SCH) in the acquisition of cell ID. The proposed algorithm classifies total S-SCH sequences into subgroups based on the correlation among sequences, and thus, the number of correlators for S-SCH detection is significantly reduced. Despite the complexity reduction, the numerical results show that the proposed algorithm provides a comparable detection probability (DP) compared with existing low-complexity approaches. To verify the performance of the proposed algorithm, the complexity analysis and analytical derivation of the DP are also presented.