The terrain of Hubei Province is very complicated, and the loss of local heavy rainfall caused by terrain is serious. The heavy rainfall of Yichang region on 15 July 2010, is strengthened by landform effects, and occurred under a good background condition. Using the upper-air observation data, surface observation data, surface intensive observation data, the Doppler radar data and LAPS reanalysis data, the background field, surface layer air flows and radar echoes are analyzed. Research indicates that both the southward moving cold air and the strengthening subtropical high promote the adjustment of surface layer atmospheric wind fields, and the flow convergence effect on the local heavy rainfall results in a lagerscale rainfall event. There are two trigger actions by the terrain in this process, one is wind lifting in the upward side, and the other is the convergence of surface layer flow circulation.