In order to improve the water desalting efficiency of biochar on coastal saline-alkali soil,a granular biochar-polyacrylamide composite (PAM-BC) was obtained by blending biochar (BC),polyacrylamide (PAM),clay minerals in this study,while the effect of different environmental materials on the salt elution of saline soil from Haixing County was studied by a laboratory soil column simulation leaching experiment.The results showed that the treatments of PAM,BC and PAM-BC,CaSO₄(CS) significantly increased the elution amount of salt compared to CK,especially for the PAM-BC treatment with highest increase of 12.3%.The main salt ions in the eluent were further analyzed,the addition of PAM-BC significantly promoted the salt ions leaching of Na⁺ and Cl^- by 11.0%~27.3% and 17.8%~42.3% than other treatments,respectively.Principal component analysis indicated that PAM-BC addition enhanced the elution of major salt ions.The total salt content of soil under PAM-BC treatment was significantly decreased by 6.0%~16.7% compared to other treatments after the leaching of soil column.Moreover,the soil water characteristic curves indicated that PAM-BC promoted the water retention of saline-alkali soil.These findings can provide a theoretical basis for the application of PAM modified biochar in the salt reduction and soil improvement in coastal saline-alkali soil.