The invention discloses post-tensioning self-resetting joints capable of multi-stage energy dissipation and an assembling method for the post-tensioning self-resetting joints. The joints can slide relative to one another, and provide energy dissipation under small deformation through a mode of unilateral friction between a T-shaped piece and a beam 
flange, with increasement of deformation of openings of the joints, an SMA 
damper connected with a T-shaped plate begins to enter a 
phase transition energy dissipation phase, and introduced 
metal damping cannot increase 
residual deformation of the joints at the same prestress level; and for avoiding the characteristic of low redundancy of the post-tensioning joints, 
contact pressure-bearing of a bolt rod connecting the T-shaped piece and the beam 
flange and the oblong hole wall of the beam 
flange is allowed through an oblong hole, and under extreme conditions, collapse can be effectively resisted. According to the post-tensioning self-resetting joints, under small to middle seisms, friction damping is used for energy dissipation, energy dissipation in a combined energy dissipation mode can be realized by cooperating with SMA 
phase transition under middle to large seisms, and by means of post-tensioning prestress reinforcements, complete resetting is realized; and under the extreme conditions, 
joint force transfer is transformed intocollapse resistance in a hole wall pressure-bearing mode, and multi-stage energy dissipation and the multi-redundancy property are realized.