The invention provides a display substrate and a preparation process of the display substrate. The display substrate comprises a display area, a retaining wall surrounding the display area and a thinfilm packaging layer. The thin film packaging layer comprises a first inorganic barrier layer, an organic barrier layer and a second inorganic barrier layer which are stacked. The display area of thesubstrate is provided with a corner part. A plurality of convex dam structures are arranged at the position, corresponding to the corner part, of the substrate. A part, corresponding to the corner part, of the first inorganic barrier layer covers the multiple convex dam structures, and a flow guide groove structure is formed in the part, located between every two adjacent convex dam structures, ofthe first inorganic barrier layer. The organic barrier layer is formed by an organic material with fluidity, and the organic material is configured to be arranged on the part, located at the corner part, of the first inorganic barrier layer under the capillary action of the flow guide groove structure.