1. A method for mapping resource units, comprising: dividing physical resource unit set to obtain a first physical resource unit set which is in a unit of N1 continuous physical resource units, and a second physical resource unit set into which the remaining physical resource units are put; permuting, in a unit of N2 continuous physical resource units, the physical resource units in the second physical resource unit set; allocating, in a unit of N1 continuous physical resource units, the physical resource units in the first physical resource unit set to each frequency partition, and allocating, in a unit of one physical resource unit, the permuted physical resource units in the second physical resource unit set to each frequency partition; wherein the step of dividing the physical resource unit set to obtain the first physical resource unit set in a unit of N1 continuous physical resource units is performed by a base station according to system configuration information and comprises: dividing, according to the number of the physical resource units in each frequency partition, the physical resource units in the physical resource unit set into parts, wherein the number of the parts is equivalent to the number of frequency partitions; in the part of physical resource units corresponding to each frequency partition, sequentially extracting (N1×pi) continuous physical resource units starting from the start unit, and putting the extracted physical resource units into the first physical resource unit set, wherein pi represents the number of sub-bands, each of which is in a unit of N1 continuous physical resource units, in the i th frequency partition.