Abstract: The surfaces of acid-functionalized carbon nanotubes (CNTs) were coated by TiO₂ produced by the hydrolysis of TiCl₄, which was converted into Ti through temperature-programmed reduction (TPR) equipment. SEM, TEM, XRD, and EDAX analyses were used to characterize the primary CNTs, as-prepared TiO₂-coated CNTs and the Ti-coated CNTs. It was found that after the functionalization of CNTs by ultrasonic-assisted acid treatment, TiO₂ was successfully coated onto the CNTs, which was reduced in TPR under H₂/Ar flow at 850℃ to metal Ti. The Ti transition layer is important for the formation of composites of CNTs with other metals.