Packaging substrate and manufacturing method thereof, and OLED display device and manufacturing method thereof

The invention discloses a packaging substrate and a manufacturing method thereof, an OLED display device and a manufacturing method thereof, relates to the technical field of display, and can prevent an outer side edge of glass cement coated on the packaging substrate from generating burrs. The packaging substrate includes a substrate, the substrate includes a bonding area used for coating glass cement, the packaging substrate also includes a first retaining wall located on the substrate, and the first retaining wall is arranged along an outer side edge of the bonding area and is used for stopping the glass cement coated on the bonding area from flowing outwards. The packaging substrate provided by the invention is used for preventing outside moisture and oxygen from entering an OLED display device.