Multilayer assembly is regarded as one of preferred structures in the nature and has been widely mimicked in the past decades. As a kind of efficient processing technology, layer-multiplying coextrusion has been applied to fabricate polymeric materials with alternating multilayer structure. By combining an assembly of layer-multiplying elements with a conventional coextrusion block, the number of layers can be multiplied conveniently followed by the enrichment of layer interfaces. Studies have found that the distinct structure endowed the final products with unique performances. Taking the carbon black (CB)-filled system for instance, the confined layer space allowed for a more compact connection between CB particles. Thus, the multilayer composites were substantiated to have higher electrical conductivity and microwave absorbing efficiency than the conventional ones where the conducting particles were randomly distributed in the polymeric matrix. Moreover, the layer interfaces in the multilayer system were also effective to inhibit the propagation of cracks in the stretching process, so that a larger elongation was achieved before fracturing, which provided a potential route to fabricate electrical materials with optimal mechanical properties.