To realize the collaborative resource utilization of industrial solid waste and low liquid limit silty clay, fluidized solidified soil was prepared using cement, mineral powder, steel slag, desulfurization gypsum and sodium sulfate. Unconfined compressive strength tests were carried out under different admixture contents, curing ages and curing environments. A strength prediction model considering admixture content and age was established, the differential laws of strength development under different curing environments were revealed, and the microscopic mechanism was expounded combined with SEM and XRD tests. The results show that the strength of solidified soil increases significantly with the increase of admixture content. At 28 days of curing age, the strength of 16% admixture content is 15 times that of 6% admixture content. The strength increases with curing age but the growth rate slows down, and the established quadratic polynomial model has high prediction accuracy (R2=0.9992). The compressive strength of multi-solid waste composite solidified soil is significantly higher than that of cement-solidified soil, and the strength difference between the two continues to expand with the increase of curing age. Curing environment has a significant effect on strength, and the strength development follows the order of standard curing > sealed curing > natural curing. The stress-strain curve exhibits four-stage characteristics. With the increase of admixture content and curing age, the peak stress increases, the failure strain decreases, and the deformation modulus E?? increases significantly. Microscopically, the formation of a dense network structure of C-S-H, C-A-S-H gels and ettringite promoted by high admixture content is the fundamental reason for the improvement of macroscopic mechanical properties.