The impact of asymmetric overload on the fixed-point adjustment coefficient of strut was analyzed through numerical simulation combined with field measurement and theoretical derivation. A two-dimensional finite element model of the deep excavation was established using PLAXIS 2D. The effect of asymmetric diaphragm wall depth and asymmetric overload on the wall horizontal deformation was analyzed. The relationship between the fixed-point adjustment coefficient of strut and the horizontal displacement of the wall was obtained by combining with theoretical derivation. Three quantitative formulas of the fixed-point adjustment coefficient of strut were proposed by considering different conditions of asymmetric overload and strut depth. Results indicate that the diaphragm walls on both sides tend to deflect towards the side with smaller overload, resulting in reverse displacement at wall-top on the smaller overload side as the difference in asymmetric overload increases. The effect of wall depth variation on horizontal displacement can be neglected when the embedded depth of the diaphragm wall is sufficient and the stiffness of the surrounding soil is relatively high. The fixed-point adjustment coefficient of strut shows an approximately linear distribution with the ratio of the overload magnitude on both sides, while exhibiting nonlinear distribution with the width and distance ratio from the excavation edge. Validation demonstrates that the proposed quantitative formulas have good applicability in engineering.