The incorporation of substituent ions such as Mg2+, Al3+, Cu2+ etc., has considerable effects on the crystal structure and hydration properties of tricalcium silicate (C3S). This paper reviews recent development on the substitution and the effect of foreign ions doping on the polymorphism, lattice parameters, lattice micro-strain and hydration behavior of C3S. The substitution principle based on the chemical structure of ions was summarized. By defining a quantity called structure difference factor D (referred to Ca2+), we evaluated the relationship between the chemical structure parameters of substituent ions and their substitution patterns, and the ability to stablize the higher-temperature forms of C3S. Furthermore, the complex relations among ionic substitution effect, polymorphism, defects and hydration properties were discussed. The problems that were still unsolved were mentioned, and the future investigation was also proposed.