A new decentralized fault line selection installation based on transient analysis and fault recording technology is given. The multi-CPU structure is used in the collection unit circuit to collect signal for each outlet and the industrial personal computer PC104 or 80C51F is adopted in the CPU. The new installation can meet the hardware request of transient analysis and has the fault recording function with huge capacity. It can call for the lately faults for consultation by using the installed waveform analysis software， thus the grounding fault can be dealt with fast on the spot. The real operation of the installation demonstrates the practicality of the design.