The invention provides a relay matching resistor selection device and method. The method is characterized by, dividing the operation voltage range of a relay to be tested into m gears, m being a positive integer larger than 1; according to the operation voltage range of the relay to be tested corresponding to each gear, selecting a matching resistor for each gear; selecting one gear, and connecting the matching resistor corresponding to the gear, a test power supply and a coil part of the relay to be tested in series to form a test loop, and detecting whether a contact part of the relay to betested acts; if the contact part of the relay to be tested acts, determining that the matching resistor corresponding to the gear is the matching resistor required by the relay to be tested; or otherwise, switching to any other gear for judgment until determining the matching resistor required by the relay to be tested. According to the technical scheme, the required matching resistor can be directly selected according to the potential signal of the contact part of the relay, so that efficiency of selection of the matching resistor for the relay can be improved.