The invention relates to an AISG topology system and an AISG slave device thereof as well as a scanning response method for the AISG slave device. The scanning response method for the AISG slave device comprises the following steps that the AISG slave devices simulates a plurality of device serial numbers, wherein each device serial number is unique; after the AISG slave device receives a scanninginstruction sent by an AISG primary device, the AISG slave device randomly selects one of the to-be-matched device serial numbers to be matched with the scanning instruction; and if matching is successful, the device serial number is reported. By means of the AISG topology system and the AISG slave device thereof as well as the scanning response method for AISG slave device, the serial numbers ofall the AISG slave devices and all serial numbers of the same AISG slave device can be scanned, the situation of scanning loss is avoided, and the situation of scanning failure is also avoided.