The inherent porosity of usual C-S-H and C-A-S-H phases renders them inherently vulnerable to freeze-thaw damage. In this chapter, we introduce an innovative strategy, organic–inorganic assembly, to enhance the cryogenic stability of usual C-S-H. We show a way to regulating the pore structure and stiffness of C-S-H by bonding polymeric chains with silicate chains, which succeeds in eliminating micro and mesopores in C-S-H and markedly enhancing its stiffness. A hierarchical CSH@polymer composite with high Young’s modulus and low-porosity microstructure is obtained. The composite shows a hierarchically aligned superstructure with no microporosity. These remarkable microstructural and mechanical features yield the super good cryogenic stability of C-S-H superstructure.