All-solution processed red, green, blue-quantum dot light-emitting diodes (R-, G-, B-QLEDs) were fabricated by using spin-coated silver nanoparticles (Ag NPs) as the cathode. In order to solve the higher turn-on voltage (Vt) compared to QLEDs with vacuum deposited Ag cathode, a combination of low-vacuum and thermal annealing drying process was used to dry the Ag NPs cathode. With this new process, the Vt of R-, G-, B-QLEDs was reduced to 1.9 V, 2.6 V, 3.2 V, respectively, which was comparable to the devices with vacuum deposited Ag cathode. The results show that the cathode treatment process may provide a new process idea for fabricating fully printing display light-emitting devices with low Vt.