The uplift bearing capacity of the spread foundation is determined by not only soil physical and mechanical characteristics but also its geometry shapes and scales. The foundation size parameters to determine the minimum quantity of concrete, and the maximum uplift bearing capacity, are key to optimize the foundation design. In order to study their effect on the uplift bearing capacity of the foundation, the undisturbed soil spread foundation in Gobi gravel soil is took as the case. Nine full size test foundations are designed, which use orthogonal test method selected column diameter, the extension angle of the foundation foot and the depth-to-width ratio as influencing factors and the uplift bearing capacity of the foundation as examining goal. The in-site static load tests are carried out in the Gobi gravel soil located northwest China. Load-displacement curves of nine test foundations are obtained and the uplift bearing capacity corresponding are concluded. An index named gradual change ratio is proposed to expressing plastic deformation characteristic of soil foundation under pull load. Meanwhile, the results of the tests show that the sensitivity sort of these geometry factors on the uplift bearing capacity is the depth-to-width ratio, column diameter, and the extension angle of the foundation foot. The conclusion achieve in this work is that adding the depth-to-width ratio in foundation design is an effective measure for improving the uplift capacity of the spread foundation in Gobi gravel soil.