Abstract: To prevent the settlement of subgrade of Qingdao-Jinan only-passenger-transported railway, a scheme was suggested that the Down-hole drill was used to penetrate the filled soil, and high pressure jet grouting technique was adopted for reinforcing and strengthening the foundation. In the course of construction, the procedure of high pressure jet grating was optimized, this method does not only ensure the safety of the existing railway operation, but also give a guarantee to railway quality under construction, then the engineering problem was solved effectively. After the optimum scheme was testified, it would have the value to be analyzed further and extended.