Random structures of silver dendriticlike cells, with the scale matching with infrared wavelengths, are prepared on the flexible conductive ITO film substrate, using the electrochemical deposition method by adjusting the experimental parameters. It is shown that the geometry of the silver dendriticlike structure can be fine-tuned by changing the concentration of PEG-20000, and, within certain limits, the branches of the silver dendriticlike structure get more exiguous with increasing PEG-20000 concentration. As a dielectric spacer, a PVA film with a certain-scale thickness is prepared and located on the silver dendriticlike cells by a vertical lifting deposition method. And a sandwich structural composite material is fabricated. The multiple passbands of infrared transmission spectra of the samples are gained, and left-handed effect is validated using a further slab focusing experiment.