5G New Radio is expected to employ multiple nu-merologies where diverse subcarrier spacings coexist to satisfy the requirements and channel characteristics of users. Since conventional autocorrelation-based time synchronization methods are designed for orthogonal frequency division multiplexing (OFDM) systems with a single numerology, they cannot be applied in OFDM-based multiple numerologies. We propose a new preamble structure for use in OFDM system with multiple numerologies. The proposed preamble is generated by overlapping multiple preamble components which have a repetitive structure and an amplified cyclic prefix. With these features, a different time metric corresponding to each numerology can be independently obtained from the proposed preamble. Then, each user can perform time synchronization process with the system parameter corresponding to their numerology, regardless of other user's numerology.