Abstract: The present disclosure discloses a self-curing fluid solidified soil composite curing agent and its application, which is composed of the following raw materials by mass percentage: 30-35% of cement, 10-20% of slag, 10-20% of gypsum, 5-8% of calcium carbide slag, 30-39% of microbial curing agent, 1-5% of self-curing microbeads. The present disclosure can effectively improve the compressive strength of the fluid solidified soil while ensuring the early fluidity of the fluid solidified soil, inhibit the shrinkage deformation of the fluid solidified soil, and improve the durability of the fluid solidified soil. The present disclosure improves the recycling rate of solid waste resources and has the characteristics of low cost and remarkable environmental protection effect under the premise of ensuring the application effect, which is suitable for large-scale promotion and application.