In order to develop a rapid and cost-effective new method to produce periodic microstructures on solid surfaces, and help to understand the physical mechanism of the enhancement of laser-induced breakdown spectroscopy (LIBS) signals induced by periodic surface microstructures, in this work, spherical copper powder with about 74 μm in diameter is used to imprint semispherical periodic surface microstructures on polyvinyl chloride (PVC) sheets under a pressure of 15 T. A platinum conducting layer about 100 nm in thickness is coated on the PVC surface by using a vacuum sputter coater and then nickel plates with the replicated microstructures on one surface are prepared using electroplating method. The signal enhancement effect induced by micro-structured surface in LIBS is experimentally observed and compared with that achieved by using flat surface nickel plate, the temperature and electron density of the induced plasma are measured according to Boltzmann plot method and the Stark broadening of H_α line of hydrogen. By systematically analyzing these results, it is concluded that the main physical mechanism of the signal enhancement in LIBS caused by the hemispherical periodic surface microstructure is due to the increased surface area of the sample that can be irradiated by the laser beam, leading to an increase in the mass of the ablated sample material when compared with that of a flat surface irradiated by the same laser beam. Comparative analysis is also conducted with experimental phenomena and signal enhancement mechanisms of using cylindrical periodic surface microstructures with a certain depth (20 μm diameter, 15 μm depth and 40 μm period). It is found that the depth of the microstructure helps to achieve better signal enhancement effects. This provides useful references for subsequent microstructure parameter design in the future. Finally, lead in aqueous solution samples is detected with surface-enhanced LIBS (SENLIBS) technique, while Pb I 405.78 nm line is selected as the analytical line. In comparison with flat nickel substrates, 23-fold detection sensitivity and slightly improved signal reproducibility can be achieved using nickel substrates with hemispherical periodic surface microstructures. The results indicate that nickel plates with hemispherical periodic surface microstructure show better analytical performance than flat nickel plates in elemental analysis of aqueous solution samples by SENLIBS.