The invention relates to special oil products for petrochemical products, in particular to special magnetic cutting oil and a preparation method thereof. The special magnetic cutting oil is suitable for lubricating, cooling, anti-attrition, and reducing attrition of tools in various processing methods of cutting, sawing, grinding, drilling, and the like of hard materials of non-metallic hard special magnetism, rock quartz, diamond, silicon crystal, and the like, and comprises the following components in percentage content by weight: 75% of base oil, 10% of animal and vegetable oil, 6% of extreme-pressure additive, 0.7% of anti-oxidant, 0.3% of static inhibitor, and 8% of oiliness additive. The special magnetic cutting oil has excellent lubricity and cooling performance, meets the requirement of enough lubricating and cooling performance of a tool and a processing workpiece, prolongs the service life of the tool, has favorable penetrating quality, ensures the surface of the processing piece to be bright, clean and smooth, and ensures lubricating and cooling during processing of non-metallic hard materials.