A lubricating oil friction modifier and a preparation method therefor and use thereof are provided. The lubricating oil friction modifier has a chemical formula of A.sub.xB.sup.y+(C.sup.).sub.y. In the formula, A is a perfluoropolyether acyl group, B.sup.y+ represents a cationic group having x amino groups and y ammonium ions, C.sup. is BF.sub.4.sup., PF.sub.6.sup., AsF.sub.6.sup., FAP.sup., TFSI.sup., Mn.sub.2O.sub.4 or ClO.sub.4.sup., x is an integer greater than or equal to 1, y is an integer greater than or equal to 1, and x+y2. The lubricating oil friction modifier has a good solubility with fluorine oil and fluorine grease, will not precipitate in the fluorine oil and the fluorine grease after being added, and can significantly improve the wear resistance of a lubricating oil such as the fluorine oil and the fluorine grease.

A lubricating oil friction modifier and a preparation method therefor and use thereof are provided. The lubricating oil friction modifier has a chemical formula of A.sub.xB.sup.y+(C.sup.).sub.y. In the formula, A is a perfluoropolyether acyl group, B.sup.y+ represents a cationic group having x amino groups and y ammonium ions, C.sup. is BF.sub.4.sup., PF.sub.6.sup., AsF.sub.6.sup., FAP.sup., TFSI.sup., Mn.sub.2O.sub.4 or ClO.sub.4.sup., x is an integer greater than or equal to 1, y is an integer greater than or equal to 1, and x+y2. The lubricating oil friction modifier has a good solubility with fluorine oil and fluorine grease, will not precipitate in the fluorine oil and the fluorine grease after being added, and can significantly improve the wear resistance of a lubricating oil such as the fluorine oil and the fluorine grease.