We report on the quantum confinement effect and field-emitting characteristics of ultrathin 3C-SiC nanobelts synthesized by a simple and low-cost microwave method. Morphological analysis indicates that the nanobelts are tens of micrometers in length, tens of nanometers in width and only several nanometers in thickness. Under 325 nm excitation, a broad emission peaked at 391 nm has been observed in the spectrum of the nanobelts, which reveals an obvious blueshift of bandgap. Field-emission measurements show that the nanobelts are promising field-emitting materials with a low turn-on field of similar to 3.2 V/mu m. Published by Elsevier B.V.