Abstract: In order to analyze welded hollow spherical joints and a whole reticulated dome in a same finite element model, based on the multi-scale simulation, the joint and a short part of each member connecting to it are divided by the solid elements as a micro-model, and the other part of a structure is simulated by beam elements as a macro-model. The length of the short part of beam is assumed as S. The incremental displacement constraint equations for the nodes on the section between the two models are derived by the basis of the plane section assumption of classical Euler’s beam theory. A method to introduce the constraint equations is deduced on the basis of an Updated Lagrangian Description method. The estimated value of S is given and the Zienkiewicz-Zhu error post-processing technique is used to confirm its validity. The elasto-plastic static stability analysis of a single-layer reticulated collapsing dome was carried out to show the feasibility and the validity of this method, considering the collapsing of joints.