The invention provides a low phase surge protection device including a voltage converter, a low phase delay detector and an output control switch. The voltage converter receives an alternate current (AC) input voltage, and converts the AC input voltage into a direct current (DC) input voltage. The low phase delay detector receives the DC input voltage to be a power source, enables a phase detection scheme by detecting whether the AC input voltage is in a stable state, and generates an enable signal by detecting a phase of the AC input voltage after the phase detection scheme is enabled. The output control switch receives the AC input voltage, and determines whether to transmit the AC input voltage to be an output voltage according to the enable signal.