There is no unified calculation standard for dust emission and pollution tax paid in various domestic coal ports.In response to this problem，by analyzing the key factors affecting coal dust emission，this paper summarizes and analyzes the main calculation formulas for dust emission at home and abroad. Based on the recommended formula for the environmental impact assessment of port construction projects，the formula dimension is defined，the wind speed parameters are revised，the concept of source strength of a dust-raising event is introduced，and the operation of the dumper is included in the calculation of unorganized emissions. Finally the calculation formula of total emission which accords with the current situation of coal port operation is constructed. The formula is used to calculate the dust emission in Huanghua port of the national energy group，and the corresponding relationship between the water spraying operation and the dust emission is obtained. The formula has an important guiding significance for government departments to calculate the amount of dust emission from ports and to collect reasonable discharge tax.