Abstract: the design of a IC Carmen control system. The system uses STC89C51 microcontroller as control core, using mfrc RF card reading and writing device to achieve the credit card door, out of the function button, also can through the pressed key realization of multi user card registering and unregistering function. Manage the door lock by controlling, managing and recording the radio frequency card, guaranteeing the safety of the users..Keywords: STC89C51; MFRC522 reader; access control