Abstract: Based on the experiments of five connections with reduced beam sections (RBS) and one ordinary connection under a cyclic loading, 3-D nonlinear finite element models were used to analyze the mechanical properties of these two types of connections using ANSYS. Based on appropriate finite element types, finite element analyses were conducted under the cyclic loading. The failure mode, ultimate load, plastic rotation angles, ductility and ability of energy dissipation of the connections with different reduced parameters were investigated. The hysteretic curves and local failure modes by finite element analyses show good agreement with those of the experiments. Analytical results indicate that an expanded plastic hinge could come into being and spread in reduced region of the beam to avoid premature brittle fracture near the butt weld of high stress. Reduced beam section connections have better ability of energy dissipation than ordinary connections, thusly RBS connection is an ideal ductility connection. Research also shows that only good welding quality can make full use of the ability of energy dissipation of RBS connections.