This paper proposes a high-speed reclosing operating method to improve for the stability in the power system. The proposed method calculates the reclosing time, taking the case of standard, in which the reclosing is not done using the generator phase angle δ, the anagular velocity ω and the field system voltage ed’. And, the execusion of reclosing time is calculated, considering the acceleration / deceleration energy of the generator in the during fault. It can be expected that the δ is suppressed by this optimum reclosing operation. Therefore, the system stability can be expected to improvement by carrying out the high-speed reclosing, when the fault arose. At present, it has been set at the value which seems to be optimum considering various problems in the reclosing time. However, in those methods, the system stability improvement effect can not be expected. It was demonstrated that the high-speed reclosing method have depression effect of the δ in the computer simulation.