Based on relevant flow rule, Von Mises yield condition and the virtual displacement principle determined by the updated-Lagrange configuration, nonlinear finite-element analysis of the tube-plate connection of K-shape by ANSYS program is studied in this thesis. In order to study the influence of main pipe to the ultimate strength of the tube-plate connection of K-shape, two geometric parameters are considered, D, diameter of the main pipe; T, thickness of the main pipe .Three typical failure modes, gusset yielding, main pipe excessive plastic deformation failure and branch local buckling are also summarized. A comparison was made between formula result and analysis of finite element stimulation to validate the veracity of the existing formula.