Abstract: To solve the initial damage, poor durability, and other problems of concrete caused by steam curing, the nano-hydrated calcium silicate polycarboxylate ether composite (n-C-S-H-PCE) was used to prepare high-strength non-steam-cured concrete. The effects of n-C-S-H-PCE on the compressive strength, hydration rate, pore size distribution, autogenous shrinkage and durability of concrete were studied using hydration heat, low-field nuclear magnetic resonance and other methods. Results show that the crystal nucleus of nano-C-S-H provides nucleation sites for the hydration products of cement, reducing the critical ion concentration K_sp of nucleation. And the induction and acceleration periods are advanced significantly. Also, the early compressive strength of concrete is improved considerably. The compressive strength of concrete increases by 64% after 1 day of curing, and the strength of concrete has no regression after 28 days of curing. The addition of the n-C-S-H-PCE refines the pore size of concrete matrix and increases the proportion of gel pores and capillary pores. As a result, the negative capillary pressure increases during the auto-drying process of concrete. Thus, the autogenous shrinkage of concrete increases. However, the most probable pore size of the concrete matrix and the cumulative volume of pores with a diameter of 50-100 nm decrease. This improves the resistance to chloride migration into concrete. The content of pores with a pore diameter larger than 14 nm (the critical pore diameter) decreases (from 0.0287 mL/g to 0.0156 mL/g). As a result, the freeze-thaw resistance of concrete is improved. The addition of n-C-S-H-PCE can reduce the porosity of concrete. In addition, with the increase of slag content, the concentration of calcium aluminate phase and Ca²⁺ decreases. In this way, the resistance to sulfate attack of concrete increases. The results provide a theoretical basis for the preparation of non-steam-cured, low shrinkage, high durability and high-strength concrete.