In order to investigate the performance of the reinforced widening embankment with geogrid under the differential settlement between the new widening subgrade and the old one,some indoor model tests were repectively designed and conducted under six conditions,including the no-geogrid and 2-layer geogrid reinforced widening embankments as well as the differential settlements of 0,20,30 and 50mm. For each condition,both the differential settlement distribution of the embankments and the strain performance of geogrid were tested and analyzed under load. The results show that placing the geogrid on the top and bottom layers of the reinforced widening embankment can effectively reduce the settlement deformation of the embankment caused by the load at the top of the embankment,that,as compared with the no-geogrid reinforced embankment,the settlement of the 2-layer one can reduce by at most 48% near the place under load at the same amount of the subgrade differential settlement,that the geogrid at the junction of the old embankment and the new widening one receives the biggest tension stress under the subgrade differential settlement,and that the geogrid can significantly homogenize the settlement distribution on the embankment surface and adjust the differential settlement of the junction in the cross-section direction of the embankment.