The present invention provides a flexible substrate, a flexible display panel and a flexible display device. The flexible substrate includes an on-off element and an insulating layer, wherein a part of the insulating layer serves as a part of the on-off element, and the part of the insulating layer serving as a part of the on-off element is separated from rest part of the insulating layer. In the flexible substrate, the part of the insulating layer serving as a part of the on-off element is separated from the rest part of the insulating layer, such that cracks generated in the reset part of the insulating layer are unlikely to extend to the region where the on-off element is located, thus the poor contact or abnormal on-off phenomenon of the on-off element can be avoided.