Nd-doped phosphate glass belt lasers pumped by laser diodes are demonstrated. The Nd-glass belt with a large cross-section and a small Fresnel number is air-cooled to provide around 18-W continuous wave (CW) output power with a beam quality factor of My2 * Mx2 = 16 * 3.2. With 6 pairs of V-grooves scribed on the edges of the glass belt, the beam quality is improved to My2 * Mx2 = 3.5 * 2.8 with output power of 13.5 W.