A method for fabricating interconnections with carbon nanotubes of the present invention comprises the following steps: forming a dual-layer that contains a catalytic layer and an upper covering layer on the periphery of a hole connecting with a substrate; and growing carbon nanotubes on the catalytic layer with the upper covering layer covering the carbon nanotubes. The present invention grows the carbon nanotubes between the catalytic layer and the upper covering layer. The upper covering layer protects the catalytic layer from being oxidized and thus enhances the growth of the carbon nanotubes. The carbon nanotubes are respectively connected with the lower substrate and an upper conductive wire via the catalytic layer and the upper covering layer, which results in a lower contact resistance. Moreover, the upper covering layer also functions as a metal-diffusion barrier layer to prevent metal from spreading to other materials via diffusion or other approaches.