Abstract: In order to discuss the reasonable plate spacing of perfobond connector, the influence of plate spacing on the shear stiffness of perfobond connector is analyzed through the push-out model test and based on the theory of elastic foundation beam. The calculation formula for perfobond shear stiffness is proposed, which accounts for the influence of plate spacing. Research results indicate that the plate spacing has little effect on shear capacity and peak slip of perfobond connector but changes the shear stiffness. Shear stiffness approximately linearly increases as the plate spacing increases, gradually approaching the single plate shear stiffness. The main influence factor for the shear stiffness of perfobond connector is the spacing-diameter ratio, which is suggested to be no less than 3.3 when multi perfobonds are arranged in parallel.