A flat panel display includes a data interface, a scaler control circuit, and a pulse generator configured to provide an independent pulse signal to the scaler control circuit. The data interface is configured to receive an image signal including a vertical synchronization pulse signal and a horizontal synchronization pulse signal. The scaler control circuit is configured to determine a vertical resolution of the image signal by counting a number of pulses of the independent pulse signal respectively between two adjacent vertical synchronization pulses and between two adjacent horizontal synchronization pulses. A method for detecting a resolution of an image signal received by the flat panel display is also provided.