Disclosed are method and apparatus for allocating radio resources. The method for allocating radio resource includes: determining, by a base station, a group of downlink sub-channels and transmission parameters related to the group of downlink sub-channels according to downlink channel characteristics and downlink interference characteristics of each resource block and a downlink bandwidth requirement of a terminal reported by the terminal, and transmitting the group of downlink sub-channels and the related transmission parameters determined to the terminal. The method and apparatus are able to allocate radio resources and determine transmission parameters based on user service requirement and system channel conditions, which greatly optimizes the system performances and improves efficiency.