The application discloses power transformer's experimental pencil, this experiment pencil includes many wires of quantity assorted of quantity and power transformer's terminal outgoing lines, the quantity of wire and power transformer's terminal outgoing lines's quantity phase -match, the one end of wire is provided with the fastener that is used for connecting power transformer's terminal outgoing lines, the other end is provided with and is used for connecting testing equipment terminal plug, before carrying out multiple experiment to power transformer, the corresponding terminal outgoing lines of all wires with power transformer be connected to the fastener of testing personnel on through the wire, only need be connected the wire of difference with corresponding testing equipment in the process of the test and to carry out different experiments, and need not to ascend a height the change connecting wire many times, so as to reduces the potential safety hazard in the process of the test.