A method, base station, terminal and communication system for selecting a component carrier are provided in the present invention. The method includes the following steps: determining the coverage range of each available carrier which can be used by the terminal; determining whether the distribution of the coverage ranges of all available carriers accords with a preset distribution mode; in the case of according with the presetting distribution mode, at least according to a rule which is determined by the distribution mode, determining a component carrier to be used. With the embodiments provided in the invention, a component carrier used by the terminal can be reasonably chosen.