Abstract: During the engineering construction period,due to the design adjustment,land transfer,lack ot tunds and other reasons,the extended service of support structures often occurs,thereby increasing the risk of construction,but numerical simulation analysis about this is rare till today.Based on practical engineering example,by using the MIDAS software and choosing rea.sonable constitutive models,the numerical simulation for supporting structure for excavation is performed.The findings show that the final maximum horizontal displacement appears at the place of the second anchors,and decreases as the axial forces decrease.With the increase of excavation depth,the ground surface settlement and the bottom uplift of excavation increase at the same time.The decay of axial forces fluctuates from 9% to 37%,and the decay is still distinct after reducing axial forces.The result of numerical simulation coincides basically with that of measurement in the trend,showing that extended use of supporting structure should arouse people’s attention.