The construction of Chinese earthquake early warning system is the main content of the national earthquake intensity quick report and early warning project. In the study and practice on the methods of determining earthquake parameters in the early warning system, scholars in and abroad found that the problem of the determination of the accurate magnitude in real time is challenging. Therefore, there is an urgent need for available real-time magnitude measurement methods to be used in the construction of Chinese earthquake early warning system. This paper briefly introduces the virtual seismologist(VS)method, describes the implementation process of VS method in the software for real-time determination of seismic parameters in China seismic network, and analyzes the process of using this method to determine the M_VS of Sichuan Changning M6.0 earthquake on June 17, 2019. Using the data of China seismic network constructed by the tenth five year plan project, the M_VS of 134 earthquakes with M≥3.0 and 24 earthquakes with M≥5.0 are measured by real-time online measurement and playback event waveform. The VS method is tested and its availability is evaluated. The results show that the M_VS determined in real time by VS method changes smoothly and has good availability. When the P-wave information of three stations is available, M_VS is measured for the first time, the average value of deviationδis 0.32, the number of earthquakes with δ≤0.5 accounted for 79%, and the average time was 20s. As time goes on, the use of more stations and available waveforms can effectively improve the accuracy of M_VS measurement. The application of this method in China seismic network is applicability and feasibility. It is an optional method for determining earthquake magnitude in real time, and has good application potential in earthquake early warning.