A multi-input low dropout regulator includes an amplifier, a first metal-oxide-semiconductor transistor, and a resistor. The amplifier has a plurality of first input terminals, a second input terminal, and an output terminal. Each first input terminal of the plurality of first input terminals is used for receiving an internal voltage. The first metal-oxide-semiconductor transistor has a first terminal for receiving a first voltage, a second terminal coupled to the output terminal of the amplifier, and a third terminal coupled the second input terminal of the amplifier. The resistor has a first terminal coupled to the third terminal of the first metal-oxide-semiconductor transistor, and a second terminal for receiving a second voltage. The third terminal of the first metal-oxide-semiconductor transistor is further used for coupling to a monitor pad, and the monitor pad is used for outputting the internal voltage.