The scanning Hartmann technology is a commonly used method to detect the imaging quality of large-aperture telescopes; however, the detection performance of different-order aberrations and the detection accuracy under different sub-aperture distributions remain unclear. Therefore, we develop a simulation model using Matlab and Zemax to study detection performance of this technology. The simulation results show that the highest 28 ^th-order aberration can be detected using the scanning Hartmann technology and that the root mean square (RMS) relative error is less than 5%. Further, it is difficult to distinguish the high-order aberration component when detecting multi-order aberrations. The usage of tangent sub-aperture distribution can better balance the detection accuracy and efficiency. The usage of a large number of sub-apertures can effectively increase the detection accuracy; however, the accuracy is slowly improved after the number of sub-apertures is increased to a certain number, while the detection time is greatly increased.