The invention relates to a converter gas dry dedusting coarse ash pneumatic conveying system. The converter gas dry dedusting coarse ash pneumatic conveying system comprises an evaporation cooling tower (1), an internal chain conveyor (2), an ash discharging main pipe (3), a pneumatic three-way distributor (5), a first ash discharging branch pipe (8), a second ash discharging branch pipe (16), a first bin pump (11), a second bin pump (19), a pneumatic conveying pipe (30) and a coarse ash bin (31), wherein the first bin pump (11), the second bin pump (19) and the coarse ash bin (31) are connected with one another through the pneumatic conveying pipe (30). The first bin pump (11) and the second bin pump (19) of the conveying system can alternately work to ensure the stability of the conveying system, so that the coarse ash conveying capacity of the conveying system is improved. The coarse ash bin (31) can be placed in a converter main workshop and can aslo be placed outside the converter main workshop, so that the ash storage and the ash conveying are free of limitations of occasions and distances. After a humidifier is eliminated, ash can be discharged by adopting sucking a tank truck in a vacuum, and no dust overflows, and therefore, the converter gas dry dedusting coarse ash pneumatic conveying system is environment-friendly.