Abstract: A 40 kg pilot oven was adopted to study the coal quality and main process parameters that affect the coke size. The research shows that the correlation indexes of coke size obtained from individual kind of coal and blended coal mainly include volatile matter of coal，shrinkage index and corresponding coke crushing strength M40. Reducing the volatile matter and shrinkage of blended coal is conducive to improving the coke size，and M40 has a high correlation with the average coke size. Increasing the bulk density of coal charging will significantly reduce the coke size, and high bulk density is one of the main reasons for the smaller size of stamp-charge battery coke than that of top-charge coke. Battery heating regime also has a great impact on coke size，in which simply prolonging the soaking time in the late coking period has a reaction on the average coke size，and only by truly slowing down the coking rate can the average coke size be increased

Key words: Stamp-charge battery coke, Average coke size, Bulk density, Blast furnace