Disclosed is a radio resource reuse method, a base station device, a terminal device, and a radio communication system. The system at least comprises two adjacent cells Ci (i=1, 2), using time-frequency resource, denoted as S for communication, which is divided into at least two resource units, each of the resource units being one time-frequency resource block. The method comprises: dividing the time-frequency resource S into N non-overlapping resource groups, denoted as RGn (n=1, 2, . . . , N), N being an integer larger than 1, and each of the resource groups comprising at least two of the resource units; and dividing RGn (n=1, 2, . . . , N), in cell Ci (i=1, 2), into two non-overlapping portions, of which, one portion is configured with an upper power density limit h(i)n and termed a primary sub-resource group of RGn, and the other portion is configured with an upper power density limit l(i)n and termed a secondary sub-resource group of RGn, wherein the sub-resource groups have the following relationships in terms of upper power density limit thereof: l(i)1/h(i)1