In order to guarantee the structural stress safety of the steel shell after shift and secondary sitting onto the dock piers of ShenzhenZhongshan link immersed tunnel tube, and verify the feasibility of optimization scheme of separating the concrete casting station and the steel shell assembly station, the refined local steel shell finite element model is established to calculate and analyze the influence of the support with different deviation on the structure. The method gives the refined stress calculation results of the most unfavorable supporting position of the steel shell structure, remedying for the shortage of the overall tube model in the simulation of detailed parts. On this basis, considering the safety margin and shipbuilding operation experience，the accuracy control requirement of the steel shell secondary sitting onto the dock piers is determined, and the safety of the design matching of the support and the compartment structure is verified.