A fabrication method of an alloy resistor includes: providing an alloy sheet having a plurality of openings spacing apart from each other and going through the alloy sheet and a plurality of alloy resistor units located between any two adjacent openings, wherein each of the alloy resistor units has an insulating cover area and a plurality of electrode ends on both sides of the insulating cover area; forming an insulating layer on a surface of the insulating cover area of the alloy resistor units by an electrodeposition coating process; cutting the alloy along a connecting portion, so as to obtain separated alloy resistor units; and forming a conductive adhesion material on the electrode ends of the alloy resistor units. An alloy resistor having an insulating layer with a smooth surface can be obtained by performing an electrodeposition coating process.