The invention discloses a flexible display substrate and a flexible display device. The flexible display substrate is provided with a display area and an adjacent peripheral area. The display area comprises a plurality of pixel units. The flexible display substrate comprises a substrate and at least one conductive wire disposed on the substrate. The conductive wire comprises at least two first conductive parts and at least one second conductive part, and the adjacent first conductive parts are electrically connected together by the second conductive part. The Young's modulus of the first conductive parts is greater than the Young's modulus of the second conductive part, and the resistivity of the first conductive parts is smaller than the resistivity of the second conductive part. According to the flexible display substrate, the conductive wire is not easy to break, and therefore the anti-bending performance of the flexible display substrate is improved, the bearable deformation of the flexible display substrate is increased, and the service lifetime of the flexible display substrate is prolonged.