The invention relates to a special commutator for transformer DC resistance testers, which is characterized by comprising MOS tubes MOS1 to MOS6, resistors R1-R6, resistors R1' to R6', capacitors C1-C6, relays A1-A6, a DC power supply DC1 and a DC power supply DC2. The test wire can be replaced with one click, and the previous test phase winding can be discharged and the current test phase windingcan be charged simultaneously. Compared with manual test wire replacement, test wire replacement by using the special commutator saves the time for each discharge and test wire replacement and reduces the workload of experimenters.