Abstract: This paper studied the treatment technology of the karst cave excavated by core-pulling test after the pile was completed. It is proposed to drill multiple holes in the pile body to form a connector through the karst cave, and proposed to combine high-pressure rotary grouting and static grouting to reinforce the exposed karst cave at pile bottom. Based on the application of an actual project in Zhongshan, The principle of connecting grouting for reinforcement of karst cave at pile bottom was expounded. The control points of parameters such as the number of grouting holes and the pressure of rotary jet injection were put forward. The process and key links of the treatment technology of exposed cave after pouring pile bottom were summarized. After the treatment of this project, the cement slurry core samples at the bottom of the pile are not less than 13.7MPa, and the static load capacity of the pile foundation is not less than 4367kN, which all meet the design requirements. The implementation of this technology is effective and can provide reference for other similar projects.