Abstract: Carbon nanotubes (CNTs) were prepared by way of electron cyclotron resonance chemical vapor deposition (ECR-CVD) using CH4 and H2 as source gases. During the preparation the Fe3O4 nanoparticle, Co nanoparticle and Fe(NO)3 sol were used as catalysts to prepare CNTs on porous silicon substrates, and the Fe3O4 nanoparticle was used singly as catalyst to grow CNTs on Si(111) and quartz substrates. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) were used to evaluate the morphology and structure of the CNTs prepared. The results showed that the catalyst affects the nucleus density and growth rate and the substrate affects greatly the morphology and growth mode by controlling the properties and distribution uniformity of catalyst. Among the different CNTs, the well-aligned carbon nanotubes are those which are prepared on porous silicon substrate with Fe3O4 nanoparticle as catalyst, as revealed in the study.