A method for fabricating a plurality of biosensors includes the steps of: providing a base with a surface; forming a carbon nanotube array including a plurality of carbon nanotubes substantially parallels to each other on the surface; forming a plurality of lead pairs on the surface, the plurality of lead pairs divides the plurality of carbon nanotubes into a plurality of first carbon nanotubes and a plurality of second carbon nanotubes; eliminating the plurality of second carbon nanotubes; cutting the plurality of first carbon nanotubes to form a plurality of third carbon nanotubes and a plurality of fourth carbon nanotubes; and fabricating a plurality of receptors to electrically connect the plurality of third carbon nanotubes to the plurality of fourth carbon nanotubes.