A repeater and a synchronization method for the same are provided. The synchronization method includes: configuring a base station to transmit an input signal during downlink transmission durations according to a time division duplex (TDD) configuration, in which the TDD configuration defines a predetermined pattern composed of an uplink transmission duration and a downlink transmission duration; configuring a processor generate a received signal code according to the input signal; configuring the processor to sample the received signal code by using a signal window to generate a target pattern; configuring the processor to dynamically compare the target pattern with the predetermined pattern according to the TDD configuration, positions of the received downlink transmission durations and positions of the received uplink transmission durations stored in a memory of the repeater, and determine whether the target pattern matches to the predetermined pattern.