Carbonate activated cementitious materials have the characteristics of low environmental impact, easy operation, and good material properties. Slow early age strength development limits its application for practical engineering. In this study, layered double hydroxides (LDHs) were used as the key material to promote the early-age performance of sodium carbonate activated slag. Combined with material characterization, isothermal calorimetry, XRD, TG-DTG, SEM and mercury intrusion porosimetry (MIP), the effect of LDHs on early age hydration reaction and products were systematically analyzed. The results show that with the increase of LDHs content, the hydration rate of sodium carbonate activated slag increases significantly. LDHs acts as a nanocrystalline nucleus site and facilitates the growth of hydrotalcite and C-S-H gels, which accelerates the formation of main hydration products in the early stage of sodium carbonate activated slag. The pore structure of the sample is improved in the early stage of hydration, and 1 d compressive strength reach up to 22 MPa.