The invention relates to a microbiological fuel cell-based pig farm wastewater treatment system. The system comprises a manure collecting tank, a mechanical grid filtering tower, a water collecting tank, an equalizing tank, an anaerobic tank, a microbiological fuel cell, an equalizing tank, a microbiological fuel cell reactor, an active carbon filtering tower and a drained water tank which are sequentially arranged according to a wastewater treatment sequence, and all above parts are connected through a water conveying pipe in order to realize wastewater circulation; and the manure collecting tank is connected with the mechanical grid filtering tower through a water pump to realize the wastewater circulation. The system combines the microbiological fuel cell with a traditional wastewater treatment technology, so the system can be applied in treatment of pig farm wastewater to recover the electric energy and realize wastewater treatment.