The invention discloses provides a cement decomposition furnace pulverized coal pre-gasification low-NOX combustion system and method, which can stably combust and effectively reduce the NOx emission,and meanwhile, improve the combustion efficiency of a decomposition furnace. The system comprises a coal feeding device, a pulverized coal pre-gasification furnace, an air distribution system and thedecomposition furnace; the air distribution system comprises a pulverized coal spraying pipe, a primary air pipe and a ternary air pipe; the coal feeding device comprises a coal bin and a coal mill;the coal mill communicates with the lower end of the pulverized coal pre-gasification furnace through the pulverized coal spraying pipe; the upper end of the pulverized coal pre-gasification furnace communicates with a reduction area of the decomposition furnace through the primary air pipe; the ternary air pipe is of a tee structure, one end thereof communicates with an external grate cooler, andthe other two branch ends respectively communicate with the middle part of the pulverized coal pre-gasification furnace and a burnout area of the decomposition furnace; a cement raw meal nozzle is arranged above the burnout area; and an ammonia spraying pipe is arranged at the top of the decomposition furnace.