Abstract: 【Objective】 The analysis of the bearing capacity of a strip foundation under the circumstance of sand overlying soft clay can provide a reference to the design of shallow footing where weak subsoil exists. 【Method】A theoretical derivation method is applied on the basis of the spread projection model, and the computation formula of strip footing bearing capacity on sand overlying clay soil is derived according to the stress analysis of the sand element beneath the footing. 【Result】 For the convenience of calculation, the determined parameters in the formula are given. According to the analysis, factors such as footing width, the thickness of the sand layer, the shear strength of sand and clay and the spread angle of the load have an influence on the bearing capacity, and they are considered in the formula. To prove the effectiveness of the formula, the bearing capacities of centrifuge models in the classic articles are calculated by the derived formula. 【Conclusion】The comparison shows that the relative errors between the formula and centrifuge experimental tests are less than 10%, indicating that the formula can be applied in computing the bearing capacity of strip footing on sand overlying soft clay.