Abstract: To address the defects such as exclusion incompatibility, poor dispersion, poor fluidity, and easy agglomeration in the combination of magnesium oxide powder and organic matrix, light-burned magnesium oxide was treated using a mechanochemical synergistic organic modification method through mixing and ball milling. The effects of modifier type, modification time, and modifier amount on the microstructure, lipophilic degree, activation index, and viscosity of liquid paraffin suspension of magnesium oxide were studied. The results show that when sodium stearate is used as the modifier, the surface of the modified magnesium oxide is coated with crumbly substances; FTIR analysis confirms the effective adsorption of straight-chain alkyl groups on the surface. Under optimal conditions (sodium stearate as the modifier, 7% dosage, 5 h of modification time), the product exhibits a lipophilic degree of 36.1%, activation index of 96.4%, and paraffin suspension viscosity of 3270 mPa·s. Furthermore, the modified powder demonstrates improved organic compatibility compared to unmodified powder