As the Mississippi River Delta for example, the author with the help of Google Earth software, put the delta into digital for analysis, and got some parameters such as depth and geomorphology. Combining with the geological sedimentary background and well logging curve, the author analyzed the characteristics of sedimentary subfacies and microfacies units of the delta. The study found that the sedimentary microfacies and subfacies of the Mississippi River delta both developed well, the continuity in transverse and longitudinal was better. The Mississippi River delta is a typical bird foot delta, which mainly influenced by fluvial factor. The deposits between tributary bay only developed on a large scale in the delta front of the bird foot delta, and also developed a lot of mouth bar. The shape of sheet sand in front mouth bar front was ligulate.