By upgrading of engineering test a number of physical, chemical and mechanical properties of the data, after five indicators of soil improved with the high-speed railway and the requirements of comparison, a high-speed rail come to use the improved soil, the method of some conclusions. Lime and soil interaction can be divided into four categories : First, ion exchange; Second crystallization sclerosis; Third ash; Fourth carbonated role. The principle is modified cement-soil cement in soil constitutes a solid core, in all the holes to form the skeleton of cement hydration, bound to soil particles. Through five indoor soil improvement, raw materials and on-site tests showed five improved soil could be used as high-speed railway subgrade fill the bottom of the bed, a test achieved the requirements to test the comparative technical and economic integration can be drawn from the high plasticity index clay could lime powder (sandy) soil cement may improve conclusions. Use nuclear density, filling sand method, three cutting techniques and methods compaction factor, it is found from the normal nuclear density greater, as high-speed railway should not be inferred from the quality of detection means compacted subgrade. Compaction and the times of the relationship between the coefficients derived from the test plan and the best the times of their relationship. After testing, the cement-soil mixture from the RCC to be controlled after less than four hours, lime and soil should not exceed 12 hours, if the pressure is lagging a long time, and then destroyed when it rolled improved soil early strength, leading to the eventual degradation compaction hard-compressed to be continuous rolling, parked for some time supplemented pressure compaction factor increased little. Improve soil strength in a certain time frame, with the additional time, it is proposed to be completed within 24 hours began rolling K30 test, the results may be distorted. Construction has improved soil mixing plant, road courses mixed mixing three have formed a more mature work, through a stringent process control can meet the quality requirements for passenger lanes. After three methods, we found that the market-mix not only overcome the "Mixed" Construction irregularity, human factors large and thickness of the requirements are strict, admixture content control difficulty and could easily lead to pollution wrong, solves the "Mixing Plant Act" low efficiency and high costs, economic, applicable, operational characteristics of this stage can be widely used. The curing agent for the improvement of the railway project is still relatively little test, the test results meet the requirement for passenger lanes relatively low cost for future exploration done to broaden the scope of modifiers. In short, the solution is to improve quality through testing that the filler packing lack of effective ways to reduce the construction cost.