In order to reduce the occurrence of cracks in the cast-in-situ concrete structure of the laminated wall panel in the subway assembly underground station, the expansion agent and the internal curing agent compound technology were adopted. Four groups of C40 concrete with benchmark group, single-mixed expansion agent, com? bined expansion agent, and light sand internal curing agent or SAP were designed. Through the concrete limited ex? pansion rate, auto-shrinkage and drying shrinkage and other deformation properties and large slab crack resistance test, the influence of the cooperative expansion effect of light sand internal curing agent on the deformation perfor? mance of micro-expansion concrete was studied. The results show that the light sand internal curing agent has the characteristics of high strength, high water absorption, high density, and can be evenly distributed in the concrete. The 14 day limited expansion rate of the shrinkage-compensating concrete mixed with light sand internal curing agent is increased by 72% compared with the group without the internal curing agent. The 60 day self-shrinkage is still in the expanded state, the expansion rate is 153×10-6，the crack resistance is significantly improved, and the overall performance is significantly better than that of the SAP internal curing agent. The synergistic expansion effect of internal curing agents on expansive concrete is proposed for the first time.