The invention relates to a connecting line dedicated to current transformer tests. The connecting line is characterized in that one end of a positive wire and one end of a negative wire are equipped with a plug, while the other end of the positive wire and the other end of the negative wire are equipped with binding posts equipped with jacks, that a button switch is disposed on the positive wire, that the plug can be inserted into a charging jack of an electric torch, and that the binding posts equipped with jacks can be connected with wires on the primary side of a current transformer. When the connecting line is used to perform a current transformer polarity test, the end equipped with plug is inserted into the charging jack of the electric torch; then the other ends of the connecting line provided with the binding posts are connected with the wires connected with the primary side of the current transformer. Current can be added to the current transformer by pressing the button switch. In addition, the electric torch can be simultaneously used to carry out illumination, thereby saving manpower and increasing work efficiency.