Abstract: In order to correct the shortcomings of the traditional soda residue soil filling method, which is complicated and time-consuming, the outdoor filling tests are carried out on the soda residue soil with different material states and ratios using the soda residue and fly ash from Shandong Haihua Group as raw materials, and the uniformity and strength of the liquid phase filling soda residue soil are improved through laboratory tests. The strength characteristics of the site filled soda residue soil are measured by the compaction tests, light dynamic contact tests and portable variable energy dynamic contact tests. The uniformity and strength of liquid-filled soda residue soil are improved and tested by using the self-made precipitator. The results show that the optimal ratio of solid mass of soda residue to fly ash is 7:3, and the maximum dry density and optimal water content are 0.88 g/cm³ and 64%. It is feasible to fill the soda residue soil by liquid phase, and the strength and the uniformity of soil with liquid phase are obviously better than those with solid phase. There is a certain stratification of the liquid filled alkaline residua soil. The electrotonic soil stabilizer can further improve the uniformity of the soil, and the optimal dosage is 0.019%. Adding 7% lime powder into the soda residua soil can effectively stimulate the activity of fly ash and greatly improve the bearing capacity of the soda residua soil. The experimental results can be used to guide the construction of the soda residue soil and further improve its filling efficiency and quality.