A method for forming a patterned array of carbon nanotubes (11) includes the steps of: forming an array of carbon nanotubes on a substrate (10); imprinting the array of carbon nanotubes using a molding device (12) with a predetermined pattern; and removing the molding device, thereby leaving a patterned array of carbon nanotubes (13). The method can effectively reduce or even eliminate any shielding effect between adjacent carbon nanotubes, and is simple to implement. The field emission performance of the patterned array of carbon nanotubes is improved.