Abstract: Based on the construction of pile foundation of Jiukong Bridge in Kaixian County of Chongqing City, different types of drilling machine and the drilling technique are compared and selected. The application of two drilling methods, namely, slurry wall and full casing, in rotary machine-drilling is introduced. Quality control methods in engineering steps including construction preparation, quality of drilling, making of steel cage, underwater concrete casting are explained, and the project acceptance method of the pile foundation and its treatment methods are proposed. Through the practice of pile foundation construction of Jiukong Birdge, the causes of common problems of rotary drilling cast-in-place pile are analyzed and effective preventive measures are put forward.