Abstract: The on-line monitoring technology of the processing products and emissions in the process industry is focused on the accurate and continuous detection of the target components. In this paper, the on-line rapid process mass spectrometer was applied to the real-time monitoring and the tracking of the reaction components based on the analysis of its characteristics. It could provide the on-line analysis data with distortion-free for the study of reaction kinetics. Compared with the traditional process mass spectrometer with logarithmic amplification technology, the on-line rapid process mass spectrometer had the characteristics of high speed even under high gain conditions due to the high-gain composite transconductance linear amplification technology. In addition, combined with the 16-bit high-speed AD converter, this instrument could achieve faster scanning speed and higher data output frequency, which could accurately capture the rapid reaction product information (such as pyrolysis) including the in-progress gas changing with time, and then reached the precise analysis and quantization of reaction characteristic. The key technical indicators, such as mass resolution, sensitivity, mass stability and long-term stability of the instrument were tested in detail. The practical application of the monitoring and control of coal pyrolysis reaction process were also carried out. The results showed that the instrument reached the basic indicators of the market mainstream mass spectrometer. However, it was found that the detection response of hydrogen was low in the high-speed scan mode. At the same time, the linear amplification technology also brought the problem of narrower dynamic range. These problems will be the authors’ next research direction.