Based on the dara of exploration and the control of karst ground subsidence in Tai’an section of Tianjing-Pukou railway line, the paper analyzes the contributing factors of ground subsidence and proposes a regional division standard of stability for this engineering project,discusses the synthetic control combining the karst grouting with the flyover,and de?scribes the specific requirement of grouting design and construction in karst regions. The op?eration practise in several years has proved that the control measures are effective.