In order to find out the influence of the number of key groups of precast-assembled nail group connector on the mechanical properties of shear keys, the push-out loading tests of single key group and double key group are carried out. The load-slip curve, failure form and shear capacity of the group specimens, combined with the numerical simulation of the three-bond group and four-bond group specimens, are used to study the bearing capacity reduction effect of the assembled shear key under the multi-bond group. The results show that the failure modes of the single bond group and the double bond group shear bond are both stud shearing, however, the number of cracks of the single bond group specimen is less than that of the double bond group specimen. The force inhomogeneity between bond groups gradually becomes obvious with the increase of load.Meanwhile, it is the fact that the distribution of the slip along the height direction is larger than that of the upper part, and the minimum slip of the interface is about 67% of the maximum, showing obvious inhomogeneity.The reduction effect of bearing capacity increases with the increase of the number of bond groups, and the reduction of double bond group, three bond group and four bond group relative to single bond group are 0.84, 0.80 and 0.72 respectively.Based on the energy method, the bearing capacity reduction effect of multi bond group due to uneven force is analyzed, and a simplified formula of bearing capacity reduction factor is proposed,which is in good agreement with the finite element calculation results.