In the Sinochem Quanzhou docks with diameter of 2.2 m and 2.6 m bored pile as the foundation, since the large-diameter bored pile in port & waterway engineering is relatively rare, the quality control of slag cleaning and concrete construction is more complex, and abnormal circumstances of basin-shaped sediment and local middle sediment occur in the early construction. The on-site analysis shows that the sand rate of the mud after slag cleaning influences directly the sediment thickness. This paper summarizes the conventional quality control technology of bored pile construction in the port & waterway engineering and puts forward more strict standards to meet the requirements of large-diameter bored pile construction quality. Adopting air lift reverse circulation combined with mud purification device, we improve significantly the quality and efficiency of slag cleaning. The device effectively reduces the sand rate of the mud from the conventional 4% ~ 6% down to less than 2%, and the bored pile integrity is further assured, so the construction quality meets the requirements of specification.