A voltage detection method for detecting a voltage source includes generating a first voltage with a first negative temperature coefficient, wherein the first voltage is related to the voltage source, generating a second voltage with a second negative temperature coefficient, wherein the second voltage is related to the voltage source, and through a comparator to connect the first voltage and the second voltage, for generating a detection result voltage without temperature coefficient according to a voltage difference between the first voltage and the second voltage, and the relationship that the first negative temperature coefficient is equivalent to the second negative temperature coefficient, to perform the voltage detection.