The Four-Quadrant Superconducting Nanowire Single-Photon Detector (QD-SNSPD) enables high-precision and rapid spot localization by measuring photon count differences across its four quadrants, showing great potential in deep-space laser communication and weak target detection. However, the recovery time effect of SNSPD introduces errors under high count rates, and spot localization under low signal-to-noise ratio (SNR) remains challenging. This study introduces a nonlinear count correction mechanism based on SNSPD recovery characteristics and derives a corrected Gaussian model for spot localization. To mitigate signal reduction on positive and negative half-axes in low-SNR environments, a non-integer power operation method is proposed. Simulations and experiments demonstrate improved accuracy with count correction at high count rates and reduced localization errors using the power operation under low SNR. Compared to classical half-axis differential localization, the 1.4-power operation reduces error by 27% at SNR < 10, while the corrected Gaussian model achieves a 70% error reduction at SNR > 50. Positioning standard deviation <0.01 spot radius can be achieved when photon counts exceed 10?.These findings provide valuable insights into high-precision spot localization and method selection for QD-SNSPD.