The invention discloses a coating preparation method of an automobile part. The coating preparation method comprises the following steps: selecting a plastic electroplating part manufactured by adopting the highlighting nickel process, and enabling the plastic electroplating part to be subjected to seven process steps: pretreatment, primer spraying, primary levelling, colored paint spraying, secondary leveling, baking, and discharging. The coating preparation method of the automobile part has the benefits as follows: through reasonable selection of materials, pretreatment process and the coating system, a diversified color effect is achieved, the prepared coating has a high plumpness, high grade of transparency and highly metallic appearance, the coating effect and color diversity are enriched, the scratch resistant and ageing resistant performances are realized without additionally arranging a protecting coating, the high-performance requirements of the surface coating of the automobile part are met, the long-term usage of the high-cost process of performing paint spraying after vacuum coating is avoided, and the production cost is further reduced.