The invention discloses a display substrate, a manufacturing method thereof and a display device. The display substrate comprises a first signal line, a first insulating layer, a second signal line, a second insulating layer and a conductive layer. The conductive layer is connected with the first signal line through a first through hole and connected with the second signal line through a second through hole. A metal electrode is arranged between the first signal line and the second signal line, a third hole is formed in the area corresponding to the metal electrode, the conductive layer is connected with the metal electrode through a third through hole, and the metal activity of the metal electrode is higher than that of the first signal line and that of the second signal line. The metal electrode, the first signal line and the second signal line are electrically connected through the cathode protection method of a sacrificial anode. The metal activity of the metal electrode is higher than that of the first signal line and that of the second signal line, so water vapor corrodes the metal electrode with higher metal activity first, and accordingly the first signal line and the second signal line with lower metal activity are protected.