The invention relates to a pair of loop resistance measuring pliers for a trolley type switch, which is good in use effect and safe and reliable. The loop resistance measuring pliers comprises a pliers body, the pliers body comprises two legs hinged with each other. A fastening and expanding bolt is in threaded connection with one of the legs of the pincers body. The free end of the fastening and expanding bolt leans against the inner surface of the other leg of the pincers body. The front end of each leg of the pincers body is fixedly connected with a pincers head. Each pincers head is provided with an assistant contact. A concave pit is excavated inside the other leg of the pincers body. The concave pit corresponds to the fastening and expanding bolt in position. The free end of the fastening and expanding bolt leans against in the concave pit. The cross section of the front end of the pincers head is semi-arc protruding outwards and providing with the concave pit. When the loop resistance measuring pliers is used to measure the loop resistance of the switch, the measuring pincers are placed inside the contact of the trolley type switch to adjust and measure the stretching amplitude of the two legs of the pincers by adjusting the expanding bolt, so that the pincers head of the measuring pincers leans against the inner side of the switch contact, and a switch resistance measuring meter is further connected to the assistant contact of the measuring pincers for measurement.