As a new type of foundation reinforcement method, split grouting had gradually entered the engineering field on a large scale. To verify its northwest in dealing with the validity and practicality of collapsible loess foundation, and guide the safety construction, first, at the scene of the building in the area for fracturing grouting reinforcement experiments, respectively after 56 d of natural foundation and composite foundation to carry on the static load test after grouting; On this basis, the 30 d water immersion test, collect some grouting microgram collapsibility, bearing capacity and quantity of the raw data, etc. According to the test results, the same materials and test methods were used to correct the tilting and reinforce the building. The results showed that: under the condition of the maximum pressure of primary grouting is 0.3 MPa and the maximum pressure of secondary grouting is 0.6 MPa, the method of split grouting with steel tube with 1:1 cement slurry and split grouting in two layers showed a good splitting effect. The bearing capacity of the loess foundation strengthened by splitting grouting method was nearly three times higher than that of the original foundation, which greatly improved the engineering properties of the loess. After grouting, more than 67% collapsibility of loess could be effectively eliminated. A new settlement calculation method based on pile-soil stress ratio for composite foundation with small pile diameter was proposed.