A method for manufacturing a thermal interface material comprising the steps of: providing a carbon nanotube array comprising a plurality of carbon nanotubes each having two opposite ends; forming a composite phase change material by filling clearances in the carbon nanotube array with a phase change material; forming a section with predetermined thickness by cutting the composite phase change material along a direction cross to an alignment direction of the carbon nanotubes; and heating up the section to a temperature higher than a phase change temperature of the phase change material and cooling down after the two opposite ends of the carbon nanotubes protruding out of the section.