The disclosure relates to a CMOS structure and a manufacturing method thereof. The CMOS structure includes a substrate and an N-type TFT and a P-type TFT on the substrate. The N-type TFT includes a first gate electrode, a first active layer, and a first gate dielectric layer therebetween. The first active layer includes a first semiconductor layer, a second semiconductor layer of the N-type, and a third semiconductor layer of the N-type which are located at opposite ends of the first semiconductor layer and sequentially stacked in a direction away from the first gate dielectric layer. An N-type doping concentration of the second semiconductor layer is smaller than that of the third semiconductor layer. The P-type TFT includes a fifth semiconductor layer and a sixth semiconductor layer. A P-type doping concentration of the fifth semiconductor layer is smaller than that of the sixth semiconductor layer.