We present a calculation model to investigate the focusing characteristics of an atomic beam in a laser standing wave, taking the wave nature of the atomic propagation into account. The effects of atom source, optical parameters of the laser field and the substrate position on atom focusing axe analyzed. Numerical simulations indicate that the best focusing performance can be obtained by repositioning the substrate or optimizing the longitudinal atomic beam speed, laser intensity and the detuning of the laser beam. The feature width of the nanostructure is mainly determined by the transverse speed distribution of atoms. Some methods for optimizing experimental parameters are suggested.