Abstract: In order to investigate the application effect of large-diameter jet grouted anchor cable in foundation pit in karst area, based on the foundation pit engineering in Baiyun district, Guangzhou city, the design scheme and implementation effect of the filling pile and large-diameter jet grouted anchor cable support system in the karst development area are analyzed in detail, and the construction technology of the large-diameter jet grouted anchor cable is optimized on-site. The results show that the construction efficiency of the large-diameter jet grouted anchor cable with the on-site optimization process is approximately 32 % higher than the conventional process. For the large-diameter jet grouted anchor cable in silty clay, in order for the diameter of the anchor body to reach 400 mm, the single-pipe jet grouted pressure must be more than 20 MPa. The deep horizontal displacement and settlement of the surrounding soil of the foundation pit supporting structure of the filling pile and large-diameter jet grouted anchor cable and the reasonable controllable range of the anti-pulling force of the large-diameter jet grouted anchor cable are adopted; the filling pile and large-diameter jet grouted anchor cable are safe and reliable as the foundation pit supporting structure in the karst development area. The research results can serve as a reference for similar excavation projects in Guangzhou.