The invention relates to a quick switch arc-extinction system suitable for high-resistance grounding faults. The system is characterized by comprising a quick switch arc-extinction device installed ona bus of a transformer substation. The quick switch arc-extinction device is connected with a synchronous measurement terminal through a phase-selecting and positioning device installed in a main control room of the transformer substation. In this way, fault data can be collected by the synchronous measurement terminal after the occurrence of a fault, and then the fault data are uploaded to the phase-selecting and positioning device to be subjected to phase selection, line selection and positioning analysis. After that, a result is outputted to the quick switch arc-extinction device for further action. The results of trials show that, by adopting the system, the hardware investment cost can be reduced, and the line selection effect can be effectively improved. Meanwhile, the damage to thepersonal safety caused by the grounding fault is reduced. Moreover, the fast and accurate grounding of a fault phase and the tripping of a fault line are achieved.