A level shifter applied in a driving circuit of a display is disclosed. The level shifter includes a first stage of level shifting unit and a second stage of level shifting unit and used to convert an input voltage signal with low voltage level into an output voltage signal with high voltage level. In one example, the total number of the transistors needed by the level shifter is much fewer than that of the prior art, and additional voltage sources are not needed to provide middle voltages. The manufacturing cost of the exemplary level shifter can be reduced and the signal level shifting efficiency of multi-power domain can be enhanced.