Boron carbide nanobelts have been synthesized successfully by carbothermal growth method. Boron oxide, activated carbon, gallium oxide and sodium chloride in the molar ratios of 1: 5: 0.03: 0.2 were used as raw materials. The width and thickness of the nanobelts range from 1 to 10 μm, and 80 to 150 nm respectively. The length is up to 50–200 μm. Diffraction peaks in the XRD pattern can be indexed to rhombohedral boron carbide with lattice parameters of a=5.616Å, c=12.067 Å. SAED pattern recorded along [ 010 ] zone axis shows (104 ) growth direction. A vapor–liquid–solid (VLS) growth process on the active catalyst surface is supposed to interpret the growth mechanism of as–synthesized nanobelts.