The present invention discloses a bearer establishing method and system based on handover, wherein the method comprises: an MME transmits the handover required message to the target base station, and carries aggregate maximum bit rate information, namely AMBR information of the UE in the handover required message. In virtue of the above technical scheme, the AMBR information is transmitted to the target base station through the interface S1-MME from the MME when the handover through the MME happens, so that the target base station can obtain the AMBR information and achieve the establishment of the bearers.