Abstract: Based on the analysis of electrical characteristics of the electric arc furnace, theoretical electrical characteristic curves of electric arc furnace were drawn. With the concept of "conomy electric current", the rea-sonable power input specification under the consideration of many relative factors was given. According to the productive process of Chinese steelmaking manufacture of electric arc furnace, the principle of secondary voltage determination and the means of device loop impedance worth ascertain was introduced. Combing the high impedance electric arc furnace technology, the power input specification of high voltage and long arc was put forward, and reasonable guarantee of power input specification wasproposed.