A sampling clock selection module for a serial data stream is disclosed. The sampling clock selection module includes a multi-phase generation circuit, a sampling circuit, a comparison unit and a logic operation unit. The multi-phase generation circuit generates a plurality of non-overlapping clock phases derived from a reference clock signal. The phase selection circuit selects a sampling clock phase under a calibration mode. The sampling circuit performs sampling on the serial data stream a plurality of times to generate a plurality of sampled values in response to the sampling clock phase. The comparison unit compares the sampled values with the serial data stream so as to update a plurality of flag signals. The logic operation unit performs a logic operation on the flag signals so as to select a sampling clock phase under a normal operation mode from the clock phases.