Based on the conventional weather chart data and NCEP reanalysis data, two cyclone induced rainstorm events on 14 May 2002 and 26 May 2013 in Shandong are analyzed. The results show that: the two processes were affected by the upper level trough, southwest vortex, and surface cyclone, but there were significant differences in the path of cold air, upper and lower level jets and air instability stratification. During the rain process of the former, the invasion of cold air was from bottom to top, and the atmospheric stratification was convective stability; the vertical isentropic surface triggered the growth of vertical vorticity and the energy release of moist symmetrical instability. The latter was cyclone waves resulted from the enhancement of cold/warm advection above a stationary front, in which the convective instability energy released through reducing the lower level stability forces warm air to lift, which was superimposed by the cold air mass above the warm moist air flow.