A method and a terminal for acquiring a frequency difference are disclosed. The method includes acquiring a difference T1 between clock timing before dormancy and clock timing of a base station, recording a dormancy period T between dormancy start and dormancy end, acquiring a difference T2 between clock timing after dormancy and clock timing of the base station, and computing a frequency difference between a low speed clock and a base station clock according to normalization frequencies, T1, T, and T2.