With the large-scale application of online monitoring technology in the primary equipment of the distribution network, false alarms caused by the performance of the monitoring terminal have occurred from time to time, resulting in great losses. Therefore, it is urgent to find an online evaluation method for monitoring terminals, one which can promptly warn about and eliminate the equipment in abnormal state in a timely manner. To this end, this paper proposes an online evaluation program for the performance of electrical equipment monitoring terminals based on 5G communications. First, 5G communication technology is used to collect data from all monitoring terminals in the area. Secondly, three indicators such as the average deviation degree are introduced, and online evaluation of the monitoring terminal is realized by comparing the difference between the collected data and the historical data. Finally, the identification of false alarm events is completed. The analysis of examples proves that the method can accurately determine the operating status of the monitoring terminal and avoid the adverse effects caused by false and omission reports. Thus it is a feasible method. This work is supported by the Science and Technology of the Headquarters of State Grid Corporation of China (No. 5500-202022072A-0-0-00).