Abstract: The excavation of foundation pits will cause additional horizontal displacement of soils, and the excessive horizontal displacement will damage the adjacent underground structures. Thus, based on the virtual mirror technology and taking full advantages of the easy measurement of deformation of retaining structures, the semi-analytical formula for horizontal displacement of soils outside pits under excavation is derived, during which the uneven shrinkage coefficient of soils is defined, so the non-uniform convergence of soils, neglected in the current researches, is considered. Then, the measured results from the published case are selected to be compared with the proposed analytical solutions. Fairly good agreements are obtained between the proposed method and the measurements. And further parameter analysis shows for the horizontal displacement of soils outside the foundation pits, the calculated results without considering the uneven shrinkage of the soils will underestimate that of the upper soil and overestimate that of the lower soil, Therefore, there is a certain deviation from the measured values. And when the soils are nearer to the foundation pits, the deviation is more obvious, so to consider the uneven shrinkage of the soils is necessary. When the non-uniform coefficient is between 3 and 6, the calculated value is in good agreement with the measured one. The proposed method can provide a new way to predict the horizontal displacement of soils induced by excavation of foundation pits.