This article proposes the transient energy model of multi-disturbance sequence, which is composed by the permanent fault and re-closing. The influence of re-closing time on the system transient stability is analyzed based on the stability margin. In this paper, a fast setting method for optimal re-closing time based on short-circuit fault trajectory is proposed. This method takes the minimum angular velocity as the initial tuning value and calculates the optimal re-closing time quickly by iterative correction of the second order sensitivity of the stability margin refer to Newton’s method. The IEEE test system case verifies the efficiency and validity of the proposed method.