Abstract: 3 h surface pressure change that is smaller than the daily pressure variation can often be found before the occurrence of severe weather processes forced by low-level warm advection. The Pressure Change Range (PCR) is defined as 3 h pressure change that is smaller than the daily pressure variation but larger than one standard deviation calculated from long-term PCR time series based on conventional ground observations. Climatological distribution characteristics of the 3 h pressure changes over central and eastern China are analyzed in the present study. The PCR index is applies to study three severe weather processes. The result shows that the standard deviation of the 3 h pressure change has a smaller daily variation compared to the mean value of 3 h pressure change over central and eastern China. The PCR is an appropriate index for measuring the anomaly of pressure change. The PCR counts in Northeast China, North China, Central China and East China area are abnormally high in winter and spring than in summer and autumn. In South China, the PCR counts are abnormally small in autumn. PCRs are mainly concentrated over low intensity range. A high PCR value often indicates that strong convective weather might happen. Cyclonic systems are primary weather systems that lead to higher PCR in Northeast China, while the decaying or rapid eastward movement of high pressure systems are responsible for higher PCRs in other regions. Higher PCR in Northeast China possibly corresponds to clouds with TBB ≤ -52℃. When the surface pressure field shows an inverted trough pattern, higher PCR always corresponds to clouds TBB ≤ -52℃. For higher PCRs induced by decaying or rapid movement of high pressure system, there exist no clouds with TBB ≤ -52℃. The three severe weather processes investigated in the present study all occurred over the area covered by an inverted trough. An obvious PCR center appeared about 3 h before the severe weather happened, and the mesoscale clouds moved to the PCR center during the process.