Abstract: To improve the structural seismic property, ductile and energy-dissipated connections represented by the reduced beam section connections gradually replace the ordinary connections. Therefore, in this paper, the beam's ultimate load under unidirectional and proportional loading is analyzed to judge the location of the plastic hinge, and the results are compared with those of the ordinary beam. It is shown that the ultimate load decreases more significantly when the beam is longer. A suitable reduced parameter should be chosen when the beam is short, to avoid the plastic hinge being formed at the end of the beam.The results can serve as the plastic design basis for the reduced beam and expand ultimate load content in structural mechanics.