At present, the structure of gabled frames is the most extensively-applied structure in the single-storey industrial building and long-span single-storey buildings. The joints of corner are main connecting part of gabled frames, of which the performance directly affects the integral behavior of its structure subject to load. At the same time, the construction of joints also determines its features of the semi-rigid stiffness. In this article, numerical simulation and experimental research are conducted to investigate semi-rigid connection of corner joints in gabled frames with different height-thickness ratios of beam-column web, width-thickness ratios of flange, and height-width ratios in corner joints. The three-folder-line moment-rotation relation model has been established and the expression concerning moment-rotation relation obtained.