Hydraulic fracturing in shale gas development may trigger the migration of acidic pollutants, posing a threat to groundwater environmental safety. Addressing the current research gap in multifield coupling effects on fracturing pollutant migration, this study focuses on a domestic shale gas well, establishing a coupled theory framework for acidic pollutant seepage-dissolution reactions. Using COMSOL software, a two-dimensional finite element numerical model was developed to systematically analyze the evolution of reservoir pressure, acidic pollutant (H+) concentration, reaction product (Ca2+, HCO3-) concentration, and reservoir porosity-permeability dynamics during fracturing fluid migration, along with parameter sensitivity analysis. Research indicate: (1) After fracturing fluid injection, reservoir pressure initially rises and then stabilizes, while H+ concentration decreases with distance from the horizontal well, whereas Ca2+ and HCO3- concentrations first increase and then decline; (2) Higher injection pressure leads to faster reservoir pressure rise and greater stable pressure, with lower fracturing fluid pH resulting in longer migration distances for acidic pollutants and reaction products; (3) The model dynamically incorporates evolving porosity and permeability influenced by chemical reactions (e.g., calcite dissolution), where injection pressure and fluid pH significantly impact these factors. Analysis reveals that neglecting porosity-permeability evolution would underestimate H+ (10%) and overestimate reaction product concentrations (2%). This research enhances scientific understanding of acidic fracturing fluid pollutant migration and provides a reference for environmental risk assessment of shale gas hydraulic fracturing sites.