A method and an apparatus for allocating spectrums are provided in the disclosure. The method includes: reconfigurable spectrums for a target group domain are calculated, wherein said reconfigurable spectrums contain one or more of a dedicated spectrum, a reusable spectrum and a loanable spectrum; during the system reconfiguration, spectrums are allocated to cells of the target group domain in a non-overlap region after spectrums are allocated to cells of the target group domain in an overlap region according to the reconfigurable spectrums. By use of the disclosure, the spectrum allocation can be implemented during the system reconfiguration, and interference can be effectively suppressed.