The invention discloses a pneumatic conveying boiler pulverized coal combustion system which is suitable for the power plant boilers, the cement kilns and the industrial pulverized coal furnaces.The combustion system comprises a primary fan, a pulverized coal silo, a powder feeder, a pulverized coal mixer, a filter, a pulverized coal burner and a connecting pipe; the filter is connected to a powder feeding pipeline of the pulverized coal burner through the pulverized coal mixer and comprises an inlet expansion cone section, a straight pipe section and an outlet shrinkage cone section; the inlet diameter of the inlet expansion cone section is phi 1, the inlet diffusion confusion angle is beta, and the diameter of the straight pipe section is phi 2, the length is L, the outlet diameter of the shrinkage cone section is phi 3, and the outlet shrinkage angle of the outlet shrinkage cone section is alpha. The system solves the problems of the fluctuation of furnace hearth combustion and theraising of the carbon content of the fly ash due to powder feeding fluctuation of the pulverized coal boiler, the filter structure is simple, the operation is convenient, the use effect is good, and the wide practicability is achieved.