Based on the optimized mixture ratio of core wall asphalt concrete, asphalt concrete specimens were prepared using 12% limestone powder, 6% cement and 6% limestone powder, and 12% cement, respectively. The effect of cement fillers on long-term water stability of core wall asphalt concrete with the natural gravel aggregate was studied. The results show that the water stability coefficient of the specimen with 12% limestone powder decreases with the increase of the immersion time, and the water stability coefficient decreases to 0.88 when the immersion time is 75h, indicating that it does not meet the requirement that the water stability coefficient of core wall asphalt concrete be greater than or equal to 0.90. The water stability coefficients of the specimens with 12% cement or 6% cement and 6% limestone powder first increase and then decrease with the increase of the immersion time, and reach their maximum values of 1.02 and 0.98, respectively, when the immersion time is 375h. The water stability factor can still meet the specification requirements when the immersion time is 1500h. It can effectively improve the long-term water stability of core wall asphalt concrete to use cement to replace limestone powder.