Abstract: The invention provides a method for fabricating a low-temperature polysilicon (LTPS) driving circuit and thin film transistor. The method includes: providing a substrate, forming an active layer, forming a gate insulating layer, forming a dielectric layer having an extending portion and forming a gate electrode. The extending portion of the dielectric layer and the gate electrode are formed during the same step, and they can serve as a mask during a later doping process so that a lightly doped source/drain region and a source/drain region are formed during the same time without forming extra masks.