In order to study the degradation law of the mechanical properties of PBL (Perfobond Leiste) shears connectors in steel-concrete composite structure under fatigue load，nine push-out PBL connectors were designed and fabricated to perform the static and fatigue tests.Among them，three static tests focused on examining the failure mode，ultimate load-carrying capacity and load-slip curves.The remaining 6 specimens were prepared for the static failure tests after a certain number of fatigue loads.Taking the cyclic number and the fatigue load ratio as the variables，the variation of the mechanical properties of the PBL connector，such as ultimate load-carrying capacity，residual slip，and shear stiffness，were obtained.The results show that：(1) PBL connector exhibits good ductility，and failure mode of the static and fatigue test specimens is all that one side of perforated steel bar cut and the other side yielded.(2) Fatigue load ratio has a significant effect on the residual strength of PBL connector.After 300 million number of cyclic loading，the ultimate load-carrying capacity is not degraded when the load ratio is 0.5，whereas it is reduced to 76.1% of initial value when the load ratio is 0.7.In the case of the same load ratio of 0.6，the load-carrying capacity tends to be slow first and then fast with the increase of fatigue cyclic number.(3) Compared with the load ratio，the residual slip is more sensitive to the fatigue cyclic number.Meanwhile，the shear stiffness is constant in the whole loading process.