In order to improve the control quality and reduce the crack risk of the secondary lining reinforced steel of doubleline large crosssection tunnel layer, the amount of sedimentation of reinforced steel is controlled according to deformation characteristics of the secondary lining reinforced steel with large span. The bearing force system of the circumferential reinforcement coincides with that of arch. The geometric parameters, arrangement of reinforced steel and cushion block and selfweight of reinforced steel are studied; the reserved sedimentation of secondary lining reinforced steel under selfweight is studied by classical mechanical theory, deflection theory of arch and the setting equation of deflection superposition under stress calculation of nonhinged arch; and it is obtained that the smaller the circumferential reinforcement, the larger the construction sedimentation, and the larger the circumferential reinforcement, the smaller the construction sedimentation. By calculating the amount of construction sedimentation of each lining reinforced steel by theoretical formula, effective presetting in advance and effective positionlimit supporting for the reinforced steel, the accuracy of the reinforced steel installation is improved, and the secondary lining reinforced steel protection layer is control.