In order to improve precision for estimating carrier frequency offset and reduce computing load, the present invention provides a method for estimating carrier frequency offset, which comprises steps of calculating a plurality of corresponding intermediate CFOs, respectively, based on one received sync sequence and one prestored sync sequences stored sync sequence through multi-step calculation, wherein, in each step, one corresponding intermediate CFO is calculated based on said received sync sequence and said pre-stored sync sequence; and weighting said plurality of intermediate CFOs in accordance with channel quality of a channel transmitting said received sync sequence to generate one final CFO. Each of the selected sequence segments may have a length and a mutual distance which are both, at its maximum, the full length of the sync sequence minus 1 so as to improve precision for the intermediate CFOs. Further, the estimation precision for the final CFO is improved by considering the impact of quality difference of reception channels on the intermediate CFOs.