An integrated dynamic bandwidth allocation method and apparatus in a passive optical network (PON) are provided. The bandwidth allocation method performed by an optical line terminal (OLT) includes generating a service level agreement (SLA) table including an SLA required for calculation for bandwidth allocation corresponding to at least one service queue included in at least one optical network unit (ONU) connected to the OLT, calculating maximum allocatable bandwidths for respective predetermined cycles based on the generated SLA table, and, when a service queue requiring bandwidth allocation is present in the ONU, performing bandwidth allocation according to different bandwidth allocation methods based on a priority level of the service queue using the calculated maximum allocatable bandwidths.