BACKGROUND: Microcystin-LR (MC-LR) is a hepatotoxin produced by cyanobacteria, which is biologically toxic, prevalent, and has serious effects on human health. Therefore, it is urgent to develop miniaturized and cost-efficient methods for MC-LR monitoring. Photocatalytic fuel cell (PFC) sensing has already been tipped as a promising approach for facile, on-site detection in environmental mediators. However, there are some tricky issues that have to be solved, such as low light utilization, poor charge separation, high manufacturing cost, and so on. RESULTS: A self-powered aptasensor was fabricated for MC-LR detection based on the PFC system that integrates In SIGNIFICANCE: This work proposed a dual-photoelectrode PFC by coupling a signal amplification of a Z-scheme photocathode, which exhibited fabulous photoelectric activity and high output power. This work may spark interest in designing new self-powered sensing devices for sensitive and convenient environmental monitoring.