The invention discloses a display substrate and a manufacturing method thereof and a display device. The display substrate comprises a flexible substrate. A plurality of pixel islands are arranged onthe flexible substrate in spaced arrays. Each pixel island comprises a display area and a packaging area surrounding the display area. A first packaging layer and a second packaging layer are sequentially formed on one side of the pixel islands away from the flexible substrate. The first packaging layer is a transparent packaging layer, and the second packaging layer is a metal packaging layer. The display device comprises the display substrate. The manufacturing method of the display substrate comprises the following steps: providing the flexible substrate; forming a plurality of pixel islands arranged in the spaced arrays on the flexible substrate, wherein each pixel island comprises the display area and the packaging area surrounding the display area; forming the first packaging layer in the packaging area of each pixel island; and forming the second packaging layer on one side of the flexible substrate on which the first packaging layer is formed, wherein the second packaging layeris a patterned metal packaging film layer, and the second packaging layer covers the edge area of the first packaging layer and the packaging area located around the edge area. The resolution of thedisplay device can be improved.