The invention provides a method for preparing an environment-friendly rubber and plastic foam product without formamide, which belongs to the technical field of foam materials and comprises the following steps: mixing, mixing nitrile rubber, polyvinyl chloride and a foaming agent composition After adding, after high-temperature mixing, it is processed into a film; compounding: adding a vulcanizing agent to the film, performing secondary compounding, and processing it into a rubber strip; foaming, extruding the rubber strip into shape, and then vulcanizing and foaming Get rubber and plastic foam products. Wherein, the blowing agent composition includes a core-shell structure, which has: a blowing agent core containing bicarbonate and nitro arc; a shell surrounding the core, wherein the softening point of the shell is higher than the temperature at which the core decomposes into gas. The rubber-plastic foamed product prepared by the preparation method of the present invention has good foaming effect, and can obtain a uniform, dense, closed-cell and independent cell structure, so that the rubber-plastic foamed product has low water absorption and thermal conductivity, and is sound-insulating. The index is higher, and it has better heat preservation, waterproof and sound insulation effects.