The invention relates to a W-flame boiler, in particular to a W-flame boiler with extended-range secondary air nozzles. The invention aims at solving the problems that the W-flame boiler provided in the background art has short pulverized-coal airflow stroke of primary air during the running and low burnout ratio of the boiler. A group of primary air nozzles, a group of exhaust gas nozzles and a group of secondary air nozzles are arranged on each furnace arch along the length direction in parallel; each group of the primary air nozzles comprises a plurality of primary air nozzle subgroups arranged at equal intervals, and an extended-range secondary air nozzle is arranged on the furnace arch between every two adjacent primary air nozzle subgroups; the extended-range secondary air is a gustof secondary air separated from the secondary air entering a hearth from the secondary air nozzles; and the extended-range secondary air is sprayed into the furnace from the extended-range secondary air nozzles at the air speed of 35-40 m/s and continues to penetrate into the hearth by being carried with the primary air with low speed (approximately being 10m/s). After the arrangement method of the W-flame boiler with extended-range secondary air nozzles is adopted, the content of the combustibles in fly ash is reduced to 5.8 percent, and the economical efficiency of running of the boiler is improved.