According to the Beijing-Zhuhai Expressway K421+642~K421+975 Subgrade disease problems, it is reinforced by dry mixed of cement rubble pile. In order to study the reinforcement effect, the test site is divided into 5 sections and each section has six piles, the length of pile is 6.0m, the diameter of pile is 150mm, the pile spacing is 1m×1m and the weight of hammer is 120Kg. The packing height of pile and the compaction number of pile per layer is different on each section. By analyzing the results of the loading tests and the dynamic penetration test, when the packing height is less than 40cm and the compaction number is more than 7, the pile body is closely dense state and bearing capacity characteristic value is 340Kpa, and meet the design requirements; The variation is comparative analyzed by the results of the CPT, Rayleigh wave test and laboratory tests of the reinforcement of subgrade before and after, the water content of reinforced subgrade is decreased, the subgrade bearing capacity and settlement is improved. Subgrade diseases have not been detected after they were treated one year. The analysis and control methods provide references for similar projects treatment.