Ethernet Passive Optical Network (EPON) is viewed by many as an attractive solution to the first mile problem. With the rapidly increasing number of user application, the capacity of current EPON has quickly become insufficient and upgrading its architecture with the wavelength division multiplexing (WDM) technology has become a natural choice. On the other hand, with more and more multimedia applications emerging in the network, providing good quality of service (QoS) to various classes of traffic is a challenge. In this paper, we propose a two-level WDM EPON upgrade solution which implements two main functions: efficient capacity scaling with bandwidth sharing at the first level, and deterministic QoS provisioning at the second level. At the first level, the scheme ensures that a minimum number of wavelengths are used for scaling. At the second level, an integrated scheme including the admission control policies and scheduling discipline is developed to guarantee deterministic QoS for multiple classes of traffic. Three different admission control policies, in particular fixed-proportional, non-preemptive and preemptive admission control, are proposed and a complete study of their unique features is presented. The simulation results show that they could all guarantee deterministic delay bounds for bursty traffic.