The present application relates to the mobile communications field, and in particular, to a technology for determining a carrier center frequency in a wireless communications system. In a method for determining a carrier center frequency, a carrier center frequency used by a base station and UE to communicate is determined according to a frequency band starting frequency, an absolute radio frequency channel number, a frequency band offset, and a relative radio frequency channel number. According to a solution provided in this application, a time for searching for a cell by a terminal can be reduced, power consumption of the terminal can be reduced, and a battery life can be extended.