Associating with highway widening project of Zhangzhou coastal main artery, the numerical analysis is carried out to analyze the lateral displacement, settlement and soil stress distribution of high fill embankment using geogrid. The results show that using geogrid can reduce the settlement and uneven displacement of high fill embankment. The maximum displacement occurs at the intersection position between old and new embankments, especially the geogrid embedding position. After the geogrid is used, vertical settlement significantly reduced while lateral displacement is in the highest flight. The lateral displacement is nearly 6cm and the total displacement is nearly 7cm, and both values are acceptable in filling construction. Meanwhile, the numerical analysis result manifests that the stress distribution of high fill embankment tends to uniform and then the whole stability of embankment increases. These conclusions may be useful to the design and analysis of reinforced-embankment of high fill and interface between new and old embankments in widened embankment.