As the actual light intensity has nonuniform spatial distribution, the surface plasmon polariton (SPP) standing wave field induced by two interference Gaussian beams is simulated using angular spectrum representation on the basis of the Kretschmann model. The Gaussian beams-induced SPP interference fringes have complex amplitude distribution, which is distinctly different from those induced by ideal plane wave. This indicates that the spatial non-uniformity of light intensity can seriously affect the distribution of exposure depth. The effects of the thickness, loss of metal films and the photoresist dielectric constant on the standing wave field are also investigated, and the results show that inappropriate metal thickness and tiny absorption loss will greatly weaken field intensity of the standing wave. Besides, the surface plasmon resonance will not be generated if the photoresist dielectric constant is too large.