The invention provides a multi-bus loop fault positioning searching device and a multi-bus loop fault positioning searching method for a protection loop. According to the multi-bus loop fault positioning searching device, real-time acquisition is performed on leakage current of all loops in the protection loop; signal processing is performed on data which are acquired by each loop; the data are uploaded to a fault analyzing module; multidimensional mode matching is performed on a characteristic rule which is arranged in a fault analyzing module system; system loop information is finally acquired; through loop analysis of the fault analyzing module, system loop distribution system information, loop state and insulation curve information of each loop are described; and particularly loops are displayed on a display screen. According to the multi-bus loop fault positioning searching device and the multi-bus loop fault positioning searching method, searching and positioning are performed on the loops which may occur in each feed line between multiple buses of the protection loop. Pairing can be performed between DC system loops of different buses. The multi-bus loop fault positioning searching device for the protection loop can perform accurate positioning and searching on the multi-bus loop fault of the protection loop.