Abstract: Marine sediment and land sediment alternately appeared frequently in Carboniferous of the South Qinlian basin.The shallow marine sediment suddently covered the underlying land sediment in large range.Facies sequence is obviously absent between them,and the marine bed is able to be tracted and compared obviously in large range,and the facies change is not obvious on horizon.It is difficult to explain the filling charact eristics with the classic gradual transgr essive and regressive mode,while it seems more reasonable to explain it with the mode of fast "inverse-irrigation".