The invention discloses a banknote CIS image acquisition method and device, an ATM and a storage medium. The method comprises the steps that if receiving of the detection signal transmitted by a detection sensor is determined, preliminary acquisition of banknote sample CIS images is controlled to be started after the preset period of time; and if the pixel points of the current acquisition row inthe preliminarily acquired banknote sample CIS images meet the formal image conditions, the starting row of formal acquisition of the banknote sample CIS images is determined in the preliminarily acquired result and formal acquisition of the banknote sample CIS images is controlled. According to the method, the starting row of formal acquisition of the banknote sample CIS images is determined so that the image background can be effectively removed, waste of resources in the image identification module and the computing time of the banknote images can be reduced and the reliability of the system can also be enhanced.