This study addresses the photon count distortion under high count rates and difficult positioning under low Signal-to-Noise Ratio (SNR) condition in Four-Quadrant Superconducting Nanowire Single-Photon Detectors (QD-SNSPD) The nonlinear correction mechanism for photon counts is introduced and an analytical solution for Gaussian spot localization problem after correction is derived. A differential localization method using non-integer power operations is proposed, which increase signal differentiation between positive and negative semi-axes through an exponent n>1 to improve positioning accuracy. Results demonstrate that count correction improves spot localization accuracy under high count rates. Non-integer power operations effectively reduce the positioning errors under low SNR conditions. Compared with classical differential localization methods, the 1.4-power operation reduces the positioning errors by 27% when SNR < 10, and the corrected Gaussian model reduces the errors by 70% when SNR > 50. When photon counts exceed 104, both the corrected Gaussian model and power operation methods (0.8≤n≤2) achieve a positioning standard deviation below 0.01 times the spot radius. These findings provide substantial support for high-precision spot localization using QD-SNSPDs.