Based on conventional active queue management (AQM), random early detection (RED) and modified random early detection (MRED) algorithms, progressive random early detection (PRED) algorithm improved by the progressive adjustment method is proposed. It regulates the packet dropping probability progressively by comparing the instantaneous queue size with the progressive maximum queue threshold parameters. Experimental results show PRED's flexibility makes itself achieve higher transmission throughput and lower end-to-end average delay for various network topologies.