The invention discloses a W flame boiler with asymmetric front wall and rear wall secondary wind, relates to a pulverized coal boiler, and aims at solving the problem of deflected internal flow fieldin a W flame boiler. The boiler comprises an upper furnace, a lower furnace, a front arch, a rear arch, multiple first pulverized coal combustion devices, multiple second pulverized coal combustion devices, multiple front arch lower secondary air nozzles and multiple rear arch lower secondary air nozzles. Each first pulverized coal combustion device comprises a front arch primary air nozzle and afront arch upper secondary air nozzle, each second pulverized coal combustion device comprises a rear arch primary air nozzle and a rear arch upper secondary air nozzle, multiple front arch lower secondary air nozzles are installed on a front wall in the width direction of the furnace, multiple rear arch lower secondary air nozzles are installed on the rear wall in the width direction of the furnace, the areas of cross sections of the front arch upper secondary air nozzles are smaller than that of the rear arch upper secondary air nozzles, and the areas of the cross sections of the front archlower secondary air nozzles are smaller than that of the rear arch lower secondary air nozzles. The invention belongs to the technical field of boiler combustion.