β-Silicon carbide (β-SiC) nanobelts with a median ridge have been synthesized for the first time via a template/catalyst-free chemical vapor reaction (CVR) method. The characterization results show that the β-SiC nanobelts with widths of 1.5 μm and thickness of about 10–20 nm consist of nanowires with rough surfaces in diameters of 100 nm (median ridge) and two symmetrical lateral flakes with uniform width. A reasonable two-step Vapor–Solid (TSVS) growth mechanism is proposed to explain the formation of the nanobelts on the basis of crystal growth theory. Using the β-SiC nanobelts as the cathode, the result of field-emission measurements shows that the turn-on field and threshold field of the β-SiC nanobelts are about 3.2 V μm⁻¹ and 5.7 V μm⁻¹, respectively. These features make the β-SiC nanobelts a promising candidate for field emission displays. The β-SiC nanobelts obtained in this work enrich the family of silicon carbides nanostructures; moreover, the method and growth mechanism could be an effective clue and example for the synthesis of belt-like nanostructures of other materials.