The effect of temperature on the properties of belite-rich cement-based (BRC) materials is different from that on Portland cement (PC). This study provides a comprehensive understanding of the mechanisms controlling strength and microstructural evolution at different temperatures, especially C-S-H characteristics, of BRC materials. Phase assemblage, pore structure, and microscopic morphology of BRC paste, as well as phase composition and structure, chemically bound water, and bulk density of C-S-H were investigated using X-ray diffraction (XRD), thermogravimetric analysis (TGA), 1H and 29Si nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). The strength of BRC mortar increased with temperature is because of the higher hydration degree of β-C2S, lower porosity (except for 60 °C), and increased main chain length (MCL) of C-S-H. Hydration degrees of 28-d β-C2S and C3S increased by 202.5% and 16.3%, respectively, while MCL increased by 39.4% from 5 to 60 °C. The higher temperature sensitivity of β-C2S is due to its activation energy being 12.4% greater than that of C3S in BRC paste. Additionally, gel porosity decreased with temperature due to decreased bound water content and increased 16.7% bulk density of C-S-H from 5 to 60 °C. Finally, the CaO/SiO2 was inversely proportional to MCL and bulk density, but positively to H2O/SiO2. The findings deepen the mechanistic understandings of the hydration kinetics and microstructural evolution for temperature-affected BRC material.