采用硅烷偶联剂对碳酸钡和浓硫酸为原料制备的超细硫酸钡进行改性，研究了偶联剂水解条件、偶联剂质量分数、反应温度和反应时间对改性效果的影响。结果表明，改性剂为硅烷偶联剂A174、改性剂质量为超细硫酸钡质量的2%、反应时间为1 h、反应温度为80℃、搅拌器转速为400 r/min时，可得到活化度为82.83%、D₅₀=342 nm的粉末状超细硫酸钡。改性后超细硫酸钡的表面疏水，其分散性能得到了较大提高，超细硫酸钡表面被改性剂所包覆，其包覆率为1.14%。

Ultrafine barium sulfate prepared from barium carbonate and concentrated sulfuric acid is modified by silane coupling agent.The influences of the hydrolysis conditions and mass fraction of silane coupling agent,reaction temperature and reaction time on the modification effect are studied.It is found that powder like ultra-fine barium sulfate with an activation degree of 82.83% and D₅₀=342 nm can be obtained when silane coupling agent A174 is used as modifier,the mass of A174 is 2% of the mass of ultra-fine barium sulfate,the reaction lasts for 1 h,the reaction temperature maintains at 80℃,and the agitator speed is 400 r·min^-1.After modification,the surface of ultrafine barium sulfate is hydrophobic,and its dispersion performance has been greatly improved.The surface of ultrafine barium sulfate is coated by modifier,and the coating rate is 1.14%.