The present invention discloses a MOS transistor having a combined-source structure with low power consumption, which relates to a field of field effect transistor logic devices and circuits in CMOS ultra-large-scaled integrated circuits. The MOS transistor includes a control gate electrode layer, a gate dielectric layer, a semiconductor substrate, a Schottky source region, a highly-doped source region and a highly-doped drain region. An end of the control gate extends to the highly-doped source region to form a T shape, wherein the extending region of the control gate is an extending gate and the remaining region of the control gate is a main gate. The active region covered by the extending gate is a channel region, and material thereof is the substrate material. A Schottky junction is formed between the Schottky source region and the channel under the extending gate. The combined-source structure according to the invention combines a Schottky barrier and a T-shaped gate, improves the performance of the device, and the fabrication method thereof is simple. Thus, a higher turn-on current, a lower leakage current, and a steeper subthreshold slope can be obtained, and the present application can be applied in the field of low power consumption and have a higher practical value.