Abstract: In geogrid reinforced aeolian sand, geonet reinforced aeolian sand and aeolian sand, full-scale in-site experiments on the bearing capacity behaviors of three groups of pad and chimney foundations, which have the characteristics of different embedment depths, widths of the bottom and heights above the ground level, and are subjected to uplift combined with horizontal loads, are carried out respectively. During the process of testing, the load-displacement behaviors, the soil reaction pressure and the rupture surface distribution are all observed. Then, based on these data, the failure mechanism is presented. It is indicated that the progressive failure mechanism can be described as compression and compaction of sand—occurrence and further development of plastic zone in sand—formation of rupture surface and entire shearing damage of subgrade. Moreover, the rupture surfaces develop asymmetrically because of the effect of horizontal loads, which is quite different from the behavior of foundation subjected to uplift load only. The reinforced materials and layer arrangement are two decisive factors for the pad and chimney foundations subjected to uplift combined with horizontal loads in reinforced aeolian sand. The geogrid increases the bearing capacity and restricts the distortion of aeolian sand mass. However, the geonet reduces the bearing capacity of the aeolian sand to some extent because it changes its form easily. The methods of increasing the embedment depth and the width of the bottom, and reducing the height above ground can be used to enhance the bearing capacity of the foundations both in reinforced aeolian sand and in aeolian sand.