Following the Dingri M6.8 earthquake on January 7, 2025, mobile location data from multiple time periods were analyzed using kernel density estimation to assess population distribution in the affected area and delineate the megaseismic region. This approach enabled the reconstruction of pre-earthquake population patterns and a detailed examination of post-earthquake population dynamics. The findings indicate that variations in population heat data effectively reflect evacuation behavior, base station outages, and disruptions to transportation infrastructure. In addition, spatial interpolation analysis of changes in mobile location data provided reliable estimates of the high-intensity zone. Overall, the use of population heat data offers a rapid and effective method for evaluating population distribution and dynamics, thereby supporting timely earthquake disaster assessment.