The invention relates to a monitoring system based on a closed tubular bus bar. The system comprises a detection terminal, the detection terminal is wirelessly connected with the monitoring system, the monitoring system comprises a current sensor arranged on the closed tubular bus bar, the current sensor is connected with a filter module via an overvoltage and overcurrent protection module, the filter module is connected with a singlechip, the filtered acquisition information is transmitted to the singlechip, the singlechip is connected with an analysis query module, the data processed by the singlechip is transmitted to the analysis query module, and the output data of the analysis query module is wirelessly connected with the detection terminal via a GSM (Global System for Mobile Communications) module. The running condition of each section of the bus bar can be conveniently viewed only by holding a display terminal on site, so that the workload and the cost of operation and maintenance are reduced, insulating performance parameters of the closed tubular bus bar can be recorded in real time, and the safety and reliability of power supply operation are improved.