Abstract: Based on the studies of source rock,storage,preservation and accumulation conditions for hydrocarbon,combined with tectonic history,core,seismic and drilling data,the main controlling factors for gas accumulation in Shaximiao Formation in Huilong area of the Western Sichuan Depression were analyzed.It was concluded that the study area was favorable for hydrocarbon generation,storage and capping.The main controlling factors included porous sand body with low impedance,boundary fault and effective trap.Typical sand body accumulation indicated that there were 3 kinds of typical accumulation assemblages; however,restricted by traps,gas accumulation size was limited.