Based on conventional observation data and NCEP 1°×1° reanalysis data, rainstorm processes of different weather types in Shandong are analyzed. It is found that rainstorm areas mainly appear at the top of surface inverted troughs on the front surface when warm and cold air interact with each other. The formation mechanism of rainstorms associated with inverted troughs is as follows. 1) The surface inverted trough is consistent with the water vapor convergence center at 850 hPa. 2) The surface inverted trough results from lower warm advection, whose center is located at the southeast wind side of the surface inverted trough. The warm advection causes obvious katallobar ahead of the warm front, which leads to the formation of the surface inverted trough. 3) The surface inverted trough lies where cold air meets warm and wet air current. On the meridional crosssection, the whole troposphere is characterized by complete, thermal, and dynamic space structure as the cold front. For the backwardtilting trough, the front lift results in strong ascending motion behind the front. As a result, rainstorms tend to appear in the northeast air current at the back of the trough. For the forward tilting trough, the strong ascending motion area is consistent with the tongue-like area of high θe, and the inverted trough front triggers the release of potential unstable energy, resulting in rainstorms associated with the inverted trough.