In the daily analysis and statistical work of thermal power plants, the real-time or historical data of data transmission monitoring system can not only reflect the real-time operating state and historical operating conditions of units, systems and equipment, but also provide production index statistics, performance calculation and economic analysis, equipment reliability monitoring and statistics. From the control level, the data transmission monitoring system collects the operation parameters and state information of the whole plant equipment, which is beneficial for the management of the power plant to monitor the operation state of the unit. In this paper, the data transmission monitoring system of thermal power plant is designed, and the application of the system is discussed. This system collects the processed signals, and this paper uses three algorithms to test. The results show that the accuracy of the traditional system is obviously lower than that of this system, and the highest accuracy of this system can reach 91.23%. This experiment confirms the correctness of this system. The data transmission monitoring system involved in this paper has obvious application advantages in safety and reliability, and promoting the integrated application of control management is of fundamental significance to the improvement of economic benefits of thermal power plants.