Direct write atom lithography is a new technique in which resonant light is used to pattern an atomic beam and the nanostructures are formed when the atoms deposit on the substrate. The motion of sodium atoms in standing wave filed is discussed. Based on the semi-classical model, this paper analyses the motion equation of sodium atom in the laser standing wave field, and then gets the trajectory of the atoms in the standing wave field by analytical simulation for different longitudinal and transverse velocities. The simulative results show that the FWHM width of stripes was 2.78 nm and the contrast was 38.5 ∶1 for the optimal longitudinal velocity, while that of the stripes was 29.1 nm and the contrast was 15 ∶1 for non-optimal longitudinal velocities. At the same time, the results show that the FWHM width of stripes was 4.2 nm and the contrast was 20 ∶1 when the divergence of atomic beam was 0.15 mrad. Whereas, the stripes presented Multi-peaked configuration and the quality deteriorated with the divergence of atomic beam increased to 1.5 mrad.