In this paper, we propose a QoS-promoted dynamic bandwidth allocation (Q-DBA) method to support quality-of-service (QoS) requirement services for Ethernet passive optical networks (EPON). The Q-DBA method classifies the three types of services: voice, video, and data into six priorities. It can not only satisfy QoS requirements of real-time service and but also improve the QoS of non-real-time packets. Simulation results show that the Q-DBA can fulfill the video dropping probability requirement while the conventional dynamic bandwidth allocation with multiple services (DBAM) fails. Also, the Q-DBA can achieve the fairness index of average data delay close to 1 but DBAMpsilas fairness index of average data delay varies greatly.