///A low signal-to-noise ratio of seismic data in complex areas has long been a major problem challenging seismic survey for hydrocarbon exploration. Based on a large number of interference seismic records and field practices, some important conclusions are drawn by progressive analytical methods from simple to complex and from individual to general. Seismic waves scatter when they meet an inhomogeneous object, i.e.a scattering source. In addition, surface scattering sources mainly include interface between two different media, the lower boundary of uneven and low sub-weathered zones, high surface relief areas especially highly steep mountain areas with high-velocity rocks, complex topography, Quaternary cover areas with great thickness, and areas with solution cavity and dissolved fractures. These understandings are of great significance to the elimination of scattered waves.