The invention relates to the field of automobile filter cleaner, and in particular, relates to a preparation method of a filter cleaner rubber slice. The preparation method at least includes the following steps: putting butadiene-acrylonitrile rubber and phenolic resin into a mixer, controlling the temperature to be 60-100 DEG C, mixing for 1-5 min, adding an auxiliary agent to the mixture, continuing to mix for 1-5 min, adding a vulcanizing agent, a curing agent and a curing accelerator to a rubber material after the rubber material is cooled, carrying out secondary mixing, and mixing for 1-5min; and placing the mixed rubber material at room temperature for 6-24 h, then vulcanizing for 1-3 min at the temperature of 220-270 DEG C, and thus obtaining the filter cleaner rubber slice.