Dihydroxylammonium 5,5 '-bistetrazole-1,1 '-diolate (TKX-50) is an energetic ion salt with high energy and low mechanical sensitivity. However, its poor morphology and low binding ability with conventional binders have significantly limited its application. In the present work, we reported a novel strategy to improve the morphology and surface properties of TKX-50 using sodium alginate (SA) as the modifier by the anti-solvent method. The results of imaging characterization indicated that SA greatly affected both crystal habit and morphology of TKX-50, resulting in modified TKX-50 granulars with low aspect ratios. The formation mechanism was explored by the molecular dynamics simulation. The XPS and SEM characterizations also revealed that SA adhered onto TKX-50 surface to form a coating layer. The non-isothermal kinetic parameters were calculated from DSC results. Our work has provided a new strategy to improve the morphology and surface properties of TKX-50 for its practical applications.