Shear wave velocity (vS), an inherent property of geotechnical materials with substantial regional characteristics, critically influences the seismic response of soil layers. Utilizing vS data from seismic safety evaluations at major engineering sites in the Heilongjiang area, statistical regressions were performed using linear, binomial, power function, and power-function-with-constant models across various soil types, including silty clay, clay, sand, gravelly soil, and weathered rock. The resulting fitting parameters and goodness-of-fit indicators for different models were obtained, providing insights into the relationship between vS and burial depth for common soil types in the Heilongjiang area. Systematic errors in vS measurements can impact seismic response calculations. Focusing on the Heilongjiang area, this study investigated how vS variability affects seismic response parameters, specifically the site amplification factor (FPGA), spectral plateau value (β), and characteristic period (T_g) under varying seismic intensities. Key results indicate the following: (1) vS increases nonlinearly with burial depth; (2) negative variations in vS generally reduce FPGA and β while increasing T_g, whereas positive variations produce the opposite effects; (3) negative variations in vS have a substantially greater influence on all three parameters than positive variations; (4) sensitivity to vS variability follows the order: T_g＞F_PGA＞β; (5) stronger input motions amplify errors caused by vS variability; and (6) for soft sites, vS measurement accuracy cannot be ignored and overestimation of test results may severely affect long-period structures.