A Nd∶YAG (yttrium aluminum garnet) nanosecond laser pulse is used in this study to ablate silicon for producing plasma spectroscopy. Further, the changes of the atomic and ionic spectral lines in the silicon plasma spectra are studied by changing the distance from focusing lens to sample surface (LTSD). The main lines discussed are Si(I) 390.55 nm and Si(II) 385.60 nm. The results show that the changes in the spectral intensities of Si(I) and Si(II) are strongly dependent on the LTSD. The spectral intensity initially increases and subsequently decreases with an increase in LTSD. In addition, the intensity of the Si(I) line is higher than that of the Si(II) line when the sample surface is located far from the focal point. In contrast, the intensity of the Si(II) line is higher than that of the Si(I) line when the sample surface is located near the focal point. At a high laser energy, more atoms in the produced plasma are ionized into ions, and the ionic line intensity is observed to increase accordingly. Changing the LTSD can optimize the spectral intensity of laser-induced breakdown spectroscopy and the ratio of ionic and atomic lines.