The invention discloses a method for preventing aluminum content in an engine lubricating oil system from exceeding a standard. The method comprises the following steps that S1, an aluminum bearing bush is cooled by liquid nitrogen, and after being cooled for a period of time, the aluminum bearing bush is arranged on a shell of an accessory case in an interference mode; S2, different axis degreesare ensured by adopting a combined machining method of reserving hard anodic oxidation size and a tool withdrawal groove; S3, wax coats the non-anodic oxidation surface of the aluminum bearing bush toform a protection layer on the non-anodic oxidation surface; S4, partial anodic oxidation is carried out on the matching surface and the locking edge between the aluminum bearing bush and a bearing;S5, the protection layer of the aluminum bearing bush of the shell of the accessory case is removed; and S6, a bearing bush inner hole is ground or the bearing is chromed to meet the fit size. The method has the beneficial effects that the problems of repeated installation, difficult machining and the like are reduced, the quality index of the aluminum bearing bush is met, and the breakdown that the aluminum content in the engine lubricating oil system exceeds the standard is reduced.