Abstract: Both nodes of reduced beam section and widened beamsection can make the plastic hinge shift away from the beam and columninterface to relieve the stress concentration in the connections, toavoid brittle fracture in weld. 3-D finite element models were used toanalyze the mechanical properties of nodes of reduced beam section andwidened beam section and ordinary nodes using ANSYS. Theanalysis results show that the bearing capacity of nodes of the reduced beam sectionis reduced due to weakened beam flanges, however, the bearingcapacity of nodes of the widened beam section is enhanced due to widenedbeam flanges. Moreover, a scopes of design parameters of thenodes are given, for seismic design of steel frames.