Abstract: Two types of gravity flow, i.e., hyperpycnal flow and slump-induced gravity flow, are divided according to the sediment supply conditions, representing the new progress in research on gravity flow sedimentology in recent years. However, there are still conceptual confusions and uncertain identifications of sediments in practical applications. Based on the data of drilling core, logging and sandstone grain size from Qikou sag, Huanghua depression, Bohai Bay Basin, a comparative analysis is performed on the differences and the identification marks of depositions between hyperpycnal flow and slump-induced gravity flow in petrology, sedimentary structure and characteristics of grain size distribution. Studies show that the favorable development sites for these two types of gravity flow in terrestrial rifted lacustrine basin are the fan delta front at fault-controlled steep slope zone, braided river-delta front at fault terrace zone, and delta front at the gentle slope zone with bending slope break. The hyperpycnal flow deposition is characterized by the development of sandy conglomerate with good psephicity of gravels, developing coarse-tail normal graded bedding or reverse graded bedding, and showing bimodal and stepwise cumulative probability distribution in grain size analysis. In contrast, the slump-induced gravity flow deposition is characterized by good sorting massive sandstones, containing plenty of mudstone fragments (ripped-up mud clasts), developing slump structure, liquefaction structure and convolute bedding, and showing normal unimodal and convex cumulative probability distribution in grain size analysis. The difference between hyperpycnal flow and slump-induced gravity flow lies in the variations of sediment supply conditions and gravity flow patterns. Fed by the flood flow, the hyperpycnal flow is mainly turbidity flow in flow pattern, with the characteristics of high water content, low density and low viscosity. Controlled by the mechanism of slumping process and secondary deposition, the slump-induced gravity flow is mainly sandy debris flow in flow pattern, with the characteristics of low water content and high density.