Aperture-scanning Fourier ptychography technology shows great potential capacity in the fields of threedimensional holographic refocusing and super- resolution macroscopic imaging. The influence of some key parameters of the technique on recovering quality is investigated. The influences of overlap ratio and size of circular apertures are studied based on light field simulation experiments using aperture-scanning Fourier ptychography iterative algorithm. The simulation results show that there is a threshold of overlap ratio under the circumstance of same aperture size, when overlap ratio is greater than the threshold, the recovering quality increases with overlap ratio raising. Under the circumstance of same overlap ratio, the recovering quality increases with reduction of the aperture size. The research results can provide guiding role for optimizing aperture parameter in the further applications of aperture-scanning Fourier ptychography.