The instability of laser energy significantly degrades the precision of laser-induced breakdown spectroscopy (LIBS) in the analysis of heavy-metal elements in soil. A phase velocity (PV) modeling framework with polarization correction was developed. The Fresnel equations and modified Sellmeier equations were employed to characterize the angular dependence of the transmittance of extraordinary ray (e-ray) on the complex refractive indices and incident angles. Using Cu, Pb, Cr, and Fe in soil samples as targets. Under seven energies, the system improved linear correlation coefficients to 0.99057 and 0.99737, the stability of recognition improved by an average of 7.271%.