To mitigate the potential seismic disasters dominated by the Longmen Shan fault zone (LFZ) in the Sichuan region, building up suitable magnitude‐estimation models for earthquake early warning (EEW) systems is important. In this article, the records from the mainshocks and aftershocks of the 2008 Wenchuan ( 7.9) and 2013 Lushan earthquakes ( 6.6), which occurred in the Sichuan region, were used to develop the maximum predominant and characteristic periods ( and ) and peak ground displacement () parameters for estimating earthquake magnitude. The developed correlations were evaluated and compared with previous studies in other regions. The parameter is correlated with magnitudes in the 4–6 and 6–8 ranges, whereas parameter scales are correlated with the entire magnitude range without evident saturation. Nevertheless, the linear slope is slightly lower than the previous studies in other regions show. As for parameter, it is confirmed as a good estimator and performs most similarly with the compared regions with the magnitude of 4–6 range. Indeed for large magnitude, we observe the saturation effect. The longer time‐window length coupled with narrowing the filtering bandwidth can improve the saturation; however, the linear slope decreases. Speculatively, the different performances can perhaps be attributed to the regional characteristics in the LFZ region. Our works offer an insight into the feasibility of the EEW system in Sichuan, China.