Abstract: A water-soluble weakly crosslinked xanthan gum (XG) was synthesized using sodium trimetaphosphate (STMP) as a crosslinker,and the synthesis conditions were optimized based on the viscosity of the STMP crosslinked XG (denoted as SP-c-XG) solutions.Effects of electrolyte (NaCl and Ca Cl₂) mass fraction (0~5.0%),p H (2~11),and temperature (20~70℃) on the rheological properties of the SP-c-XG solutions were investigated and compared with those of XG solutions.The results show that,under the studied conditions,the rheological curves of both SP-c-XG and XG solutions are pseudoplastic and can be described by Herschel-Bulkley model.The yield stress,apparent viscosity and dynamic moduli of the SP-c-XG and XG solutions initially decrease and then increase with increasing electrolyte concentration,but they initially increase and then decrease with increasing p H.Increasing temperature results in a decrease in these rheological parameter values for both SP-c-XG and XG solutions.The rheological properties of the SP-c-XG solution are similar to those of the XG solution.However,compared with the XG solution,the SP-c-XG solution exhibits higher yield stress and apparent viscosity,especially stronger elasticity and temperature resistance,indicating its use potential in enhanced oil recovery.