Abstract: A detachable printer mounting hardware comprises a computer mainframe, which has an elongated recess on a top edge thereof with a set of retaining holes and a printer-terminal connector at one end and two parallel rails at two opposite sides, and a printer housing detachably inserted into said elongated recess, which has two sliding grooves on two opposite sides for engaging said parallel rails respectively, a power switch on a top edge thereof, a set of hooks at one end releasably hooked in said retaining holes and a set of I/O pins connected to said printer-terminal connector.