The queueing management strategy of quality of service(QoS) was analyzed as a key point. First, the performances of first in first out (FIFO) queueing mechanism and priority queuing (PQ) mechanism were obtained and compared. It was found that PQ mechanism could reduce the average delay of the higher priority traffic, but the time jitter was still not under control. Therefore, an improved algorithm based on PQ mechanism was developed to solve this problem. The simulation results showed that the delay jitter was decreased significantly by the improved algorithm, and the delay jitter was improved when the data packets of different initial time delay were queued in the nodes.