Color fine-tuning of carbon nanotubes@ anodic aluminum oxide (CNTs@AAO) composite thin films is achieved via isotropically etching porous AAO in phosphoric acid before CNTs growth. With the increase of etching duration from 0 to 17.5 min, the interference band with the maximum reflectance (B-max) in visible region of the composite thin film shifts from,similar to 632 (salmon pink) to similar to 498 nm (cyan).