A display substrate and an OLED display device, the display substrate including a water absorbing structure disposed on the display substrate that is configured to be capable of absorbing moisture in the display substrate. In the embodiments of the present invention, by providing a water absorbing structure in the display substrate, it is possible to protect the organic luminescent unit from moisture released in the process of manufacturing and operating the display substrate, enhance the performance of the OLED display device and prolong the service life of the OLED display device.