Industrial iron towers are widely used in high-voltage power transmission lines, communication antennas, and other fields. However, the height and structural characteristics of the towers make them susceptible to lightning strikes. Lightning strikes are sudden and highly destructive, and their hazards are related to the impact characteristics of lightning signals such as high current intensity and short duration. In response to the current situation of lightning detection, a passive lightning current sensor is applied to collect lightning current signals. A new type of infrared fiber optic modulator-demodulator is designed to process lightning signals by transmitting them stably to the detection terminal via S/PDIF optical fiber for lightning signal detection and processing in complex industrial environments. Finally, utilizing 5G technology, the measurement data is transmitted to a cloud server for analysis. Users can access the cloud server via a mobile App or Web interface for remote lightning monitoring. Experimental results show that when lightning events occur on industrial iron towers, the monitoring system can accurately record the timing, frequency, and intensity of lightning strikes, providing a stable and reliable technical means for widespread lightning activity monitoring.