The presence of large quantities of sediments in urban drainage systems can lead to pipeline blockage and overflow contamination on rainy days. Ultrasound, as a clean physical treatment method, can destabilize sediment aggregates, and thus remove sediment during the dry season to maintain sewer function. To investigate the feasibility and optimal treatment conditions of ultrasonic technology for actual dredging, orthogonal experiments were designed to explore the effectiveness of ultrasonic dredging and the impact of five key factors on ultrasonic dredging. The results showed that the ultrasonic treatment exhibited good effects on improving the pipe siltation, with the shear resistance of sediments (EPS) reduced to 26.4%-91.5% of the control group after ultrasonic action, and a large number of EPS associated with adhesion were decomposed in the pipe sediments. Correlation analysis showed that the damage of EPS was an important reason for the decrease in the scour resistance of the sediments. The order of the impact of five key factors on ultrasonic dredging is: ultrasonic power>probe distance from mud surface>action time>sediment thickness>ultrasonic frequency. The optimal working conditions of ultrasonic dredging are: power 220 W, frequency 50 kHz, processing time 200 s, distance from the sediment surface of 3 cm. Explored the variation of dredging effect with sediment thickness, and found that ultrasonic dredging has a good effect on sediment with a thickness of ≤7 cm, and obviously decayed beyond this range. Based on this, further exploration was conducted on the changes in the properties of sediment along the depth direction after ultrasonic action.