Abstract: Taking the geothermal development process of Kaifeng Zhenyu Garden as the study object,a three-dimensional sandstone pore thermal reservoir multi-field coupling model of temperature field-chemical field-seepage field was constructed using the TOUGHREACT program,accompanied by the sensitivity analysis of the main influencing factors to investigate the influence of the geothermal reinjection process on the chemical plugging process of the geothermal reservoir. In the thermal reservoir,the minerals such as calcite,quartz,illite,calcium-montmorillonite,and silica dioxide will precipitate. However,the minerals like potassium feldspar,sodium feldspar,and dolomite will dissolve in the geothermal reservoir. Among them,calcite is the main precipitated minerals,which may block the geothermal reservoir of backfill wells,resulting in a porosity reduction of about 10%. The changes of backfill water injection flow rate,temperature,and well spacing during the backfill process affect the precipitation of calcite in the backfill process of geothermal water,thus lead to variation in the porosity of the geothermal reservoir.