The invention discloses a method for distributing bandwidths for collected available bit rate service in a grouping network and relates to the field of data communication, which is designed to solve the problems of ensuring the minimum bandwidth of an ABR service flow and dynamically adjusting the speed of the service flow between a peak speed and a lowest speed simultaneously. The invention carries through flow distribution on each available bit rate flow, the data in each available bit rate flow is grouped and divided into a part of ensuring the minimum speed and a part of exceeding the lowest speed according to the actual speed, which are respectively distributed into a bandwidth ensuring data array and an available bandwidth different expending array for treatment. The invention is suitable for distributing bandwidth for the collected available bit rate service in the grouping network.