A cascade-arch-firing low-NOx and high-burnout configuration (CLHC) was proposed as a solution for the W-shaped flame furnace's incompatibility problem of strengthened low-NOx combustion and high burnout. Numerical simulations verified by industrial-size measurements of a 600 MWe W-shaped flame furnace were used to confirm the CLHC's low-NOx and high-burnout characteristics and evaluate its cascade-arch configuration effect on the gas/particle flow, coal combustion, and NOx formation. The furnace with the existing low-NOx combustion art showed NOx emissions of about 900 mg/m3 at 6% O2 and carbon in fly ash of about 5%. In applying CLHC as a replacement for the prior art, numerical simulations at typical cascade-arch configurations of CL = 1/5, 1/4, and 1/3 (CL signifying the ratio of the lower arch depth to the total arch depth) showed that as CL increased, both the flow field and combustion symmetry initially improved but then deteriorated. In conjunction with the improvement in both NOx emissions and burnout, the CL = 1/4 setting achieved the best furnace performance with NOx emissions 707 mg/m3 at 6% O2 and carbon in fly ash of 5.5%. In comparison with the prior low-NOx art, CLHC reduced further NOx emissions by 22% and almost maintains the burnout rate.