In order to understand the influence mechanism of low temperature on the strength of cemented backfill, a large-scale cemented backfill model was modeled and analyzed by using b4cast finite element software based on maturity theory. The time-varying law of temperature field and strength of the cemented backfill in low-temperature backfilling environment were obtained. In addition, the curing mechanism of cemented backfill at low temperature was revealed by means of X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that at the initial filling temperature of 5℃, the temperature and strength of the cemented backfill increase gradually from the center of the filling body to the surrounding rock. The temperature inside the large-volume cemented backfill rises very slowly, and the central temperature only reaches 12.5℃ after 28 days. Through XRD and SEM analysis, it is found that the main hydrates in cemented backfill are ettringite and C-S-H gel. The formation rate of ettringite in low temperature determines the development of early strength of cemented backfill.