A level shifter ESD protection circuit with power-on-sequence consideration used for receiving a first signal and outputting a second signal is provided. The level shifter circuit includes an inverter, a first switch, a second switch, a voltage level shifting circuit, a first ESD clamp and a second ESD clamp circuits. When the first power supply has been powered on and the second power supply is off, the first and second switches will remain off resulting from the power-off of the second power supply. Therefore, the second power source would not be affected by the first power supply because of passing through the ESD protection circuit.