By analyzing the characteristic of decaying component of the fault phase shunt reactor current under different type of faults， a new criterion for single-phase adaptive reclosure is proposed. In this method， fault type can be identified through different variation trends of the decaying component. When permanent fault occurs， the energy of the shunt reactor will be discharged to earth through the fault point， so the decaying component will degrade to zero gradually; When transient fault occurs， the extinction and restrike of the secondary arc and the resonant component， which appears after the secondary arc is completely extinguished， force decaying component to follow the variation. Thus， by detecting the different variation trends of the decaying component， whether the fault is transient or permanent can be recognized. A large number of ATP/EMTP simulation results show that the method can identify the fault type rapidly and precisely. Furthermore， it is immune to the length of transmission lines， extinguished time of secondary arc， fault location and sampling frequency， etc.