A display device includes a first storage unit and a display chip. The first storage unit stores first extended display identification data comprising a plurality of first preset parameters. The display chip includes a control unit. The control unit provides at least one second preset parameter to replace a part of the first preset parameters in the first extended display identification data in response to a control signal and thereby generate second extended display identification data. The display chip issues a notification signal to notify the display signal providing device to read the second extended display identification data in response to a generation of the second extended display identification data. The display signal providing device provides a first display signal compatible with the second extended display identification data to the display device after reading the second extended display identification data. An extended display identification data replacement method is also provided.