A banknote counting method of a banknote counting device (100) is provided. The banknote counting device (100) is provided with a plurality of banknote storing regions, and the banknote counting method includes the following steps: detecting the denomination of a banknote currently counted in real time during a banknote counting process (S10); putting the banknote currently counted into a corresponding banknote storing region according to the denomination (S20); determining whether the banknote of the denomination is the first one in the banknote counting process (S30); if yes, calculating the current quantity of the banknote in the banknote storing region (S40); and if not, adding “1” to the original quantity of the banknote in the banknote storing region to calculate the current quantity of the banknote in the banknote storing region (S50). The banknote counting device (100) and the method can classify and count the banknotes to be counted according to the denominations, and can calculate and display in real time the quantity of counted banknotes of each denomination, the amount of the banknotes of each denomination, and the total quantity and total amount of all the banknotes after counting, thereby greatly reducing the workload of bank staff and improving user experience.