Abstract: For the semi-rigid joints of beams and columns connected by two T-shaped steel joints with different thicknesses, the variation of bolt pre-tightening force, hysteretic behavior and stiffness degradation were analyzed by experiments and finite element simulation methods. The results showed that during the quasi-static loading process, the bolt pre-tension attenuation on the column was slower than that on the beam; the increase of the thickness of the T-shaped steel could improve the strength, stiffness and energy dissipation performance of the joint. Degradation meant that an appropriate increase in the thickness of the joint could improve the seismic behavior of this type of joint.