After a large-scale blackout, reasonable and orderly restoration is of great significance for minimizing the loss. The process of network reconfiguration is investigated specially from the point of switching in transmission lines. Taking lines’ operational reliability into consideration, a method of optimizing units’ restoration sequence is proposed. Firstly, a severity index in terms of the outage loss criteria is put forward to improve the definition of lines’ restoration risk corresponding to reconfiguration scheme. Secondly, a time-step frame of reconfiguration simulation accordant with the actual situation is established by means of interactive simulation between network reconstruction and units’ restoration. Furthermore, the model of optimizing units’ restoration sequence is constructed based on minimizing lines’ restoration risk corresponding to reconfiguration scheme and solved by the cross particle swarm optimization and Floyd algorithm. The outcome of its application on the New England 10-unit 39-bus power system indicates that units’ restoration sequences obtained fully consider possible spare paths for restoration as well as minimization of outage loss. Therefore, the method proposed can more effectively cope with the potential failure during switching in lines. This work is supported by National Natural Science Foundation of China (No. 51277076).