Packet scheduling algorithm is an important element to provide quality of service (QoS) guarantee. Traditional per-flow packet scheduling methods are often not able to support good scalability. While, the non-per-flow-differentiated methods usually can not provide service guarantee for very individual flow. DPS (dynamic packet state) provides a method to support guaranteed service without per-flow control. It can provide both the service performance and scalability. But its per-packet scheduling results in high computational complex are related with the number of packets. A packet scheduling algorithm with multi-level FIFS queues, which is based on DPS, is provided in this paper to get guaranteed service. And the constrained conditions to delay guarantee under this algorithm is also provided. The theoretical analysis and simulations show that the algorithm can schedule packets with constant time complexity and the same delay performance as DPS.