The invention discloses a data interaction bus design method for household appliances, wherein the bus comprises a master device and a slave device, a communication protocol of the data interaction bus of the household appliance occupies two pins of the MCU, which are respectively named as AT and CD lines, and the whole communication process includes Q timing, E timing, W timing, discrimination domain, T timing, R timing, and Y timing. The invention has the advantages that the double-checking of the timing control with time domain discriminating technology is used to be more reliable than thetraditional interface; the CRC check may be added by self-determination, which is more humanized than the traditional protocol, and the anti-interference ability is stronger under the harsh environment, while the check is disabled under a good environment to improve the bus usage; the hardware interface device that conforms to the protocol may obtain power at least thereon regardless of the insertion direction, which is more reliable in contact as the power supply has multiple contacts compared with the traditional interface; and the physical layer interface may be customized on the NC line toadd and delete pin functions, and other software protocols may be customized on the NC line.