A banknote temporary storage device includes: a timing unit, configured to obtain a time period between a time when the front end of a banknote enters into a first sensor and a time when the back end of the banknote leaves the first sensor; a calculating unit, configured to calculate a width of the banknote based on the time period, calculate a bump radius based on the width, and determine a condition of generating a bump on the storage coiling block; a detecting unit, configured to detect whether the condition of generating a bump on the storage coiling block is met, based on a real-time radius; and an interval control unit, configured to change an interval between banknotes on the storage coiling block in a pre-set control manner to eliminate a bump, in a case that the condition is met.