A processing device and method for time domain change of A/V data stream comprises a starting threshold setting unit for setting a starting threshold; a detecting module for detecting whether the A/V data stream having a SCR domain change; a counting unit comprising a counter for recording a continuous probable times of the SCR domain change according a detecting result of the detecting module; a comparing unit for comparing the counter with the starting threshold; and a time domain change procedure performing unit for performing a time domain change procedure of the A/V data stream for synchronization of a STC according a detecting result of the comparing unit. Accordingly, since the frequency of the time domain change will be lower, the corresponding response of the decoder will be in time for playing as well.