Photoreduction, especially laser-reduction, is a clean and controllable micro- and nano-fabrication method which has been applied in the field of spectroscopy, fluorescent imaging and three dimensional (3D) fabrication. The in situ reduction of Ag+ with ultraviolet nanosecond laser lithography is focused, which is much time-effective compared with two(multi)-photon absorption reduction. Combined with ultraviolet and visible light reduction, different sub- micron gratings with large area and different surface morphology are fabricated. The reduction mechanism based on the roles of laser reduction time is discussed, Ag+ concentration and light wavelength. The gratings compose of a large number of close-packed Ag nanoparticles which are of importance for surfaceenhanced Raman scattering. The performance of surface-enhanced Raman scattering is demonstrated by tracing naproxen.