The invention discloses a hydrophilia paraffin microcapsule and an early-strength low-hydration-heat-releasing cement system for low-temperature well cementation.The cement system comprised, by weight, 100 parts of silicate and aluminate composite cement with the mass ratio of 3:7-5:5, 5-10 parts of phase-change heat absorption materials, 10-25 parts of density reducing materials and 58.2-77.2 parts of water.The cement system has the advantages that the early strength is high, and the early-strength characteristic of the system at the low temperature is excellent compared with a conventional G-grade oil well cement system; the amount of heat released during hydration is small, the amount of the hydration released heat and system temperature rising generated by the hydration released heat of the system in a 24-h hydration test are low compared with the conventional G-grade oil well cement system, and the stability of deepwater stratum hydrate can be guaranteed accordingly; the compatibility of the system with early strength agents and retarders is good.