Self-compacting solidified soil has been extensively utilized in various backfilling projects due to its advantages such as on-site soil extraction, synergistic disposal of construction waste, self-leveling, and pumpability. This study investigated the influence of liquid limit of raw soil on the engineering properties of self-compacting solidified soil through a series of tests including fluidity, bleeding rate, wet density, drying shrinkage, and unconfined compressive strength tests, complemented by free water separation tests to further explore the role of free water content in strength characteristics. The results demonstrate that under identical cement content and water-to-soil ratio, the freshly mixed slurry of self-compacting solidified soil made from high liquid limit clay exhibits lower fluidity but higher unconfined compressive strength after curing. With an increase in the water-to-soil ratio, the increment in fluidity of the freshly mixed slurry remains relatively constant, while the reduction in unconfined compressive strength after curing begins to diminish. Regardless of the curing age, the content of free water in self-compacting solidified soil made from high liquid limit clay is consistently lower. At a curing age of 7 d, the free water content in self-compacting solidified soil made from high liquid limit clay is only 2.2%, compared to 11.7% in samples made from low liquid limit clay. This research unveils the mechanism by which different liquid limits of raw soil affect the free water content in self-compacting solidified soil, offering scientific guidance for the selection of raw soil and the design of its mix proportion in engineering applications.