The Weighted Fair Queuing (WFQ) scheduler has received much attention due to its nice properties of bandwidth guarantee and bounded delay. However, the queuing delay bound of a communication session is tightly coupled with the session's allocated share. To receive a low queuing delay, a session must reserve a high share. In this paper, we study a new fair queuing algorithm called Priority-based Weighted Fair Queuing (PWFQ). PWFQ combines a session's allocated share to achieve the bandwidth guarantee and the session's priority to adjust the delay bound inside a sliding window. The new algorithm decouples the delay from the service share so that a session with a low share but a high priority may still receive a small delay. We analyze the worst-case delay bound of PWFQ and propose a simple heuristic algorithm to assign session priorities.