Dual-layer flexible circuit board substrate

The utility model discloses a dual-layer flexible circuit board substrate having a controllable bending state and belongs to the field of circuit board manufacturing technology. The dual-layer flexible circuit board substrate is in a layered structure and is provided with an insulation protection layer, a copper foil layer, a flexible substrate layer, a copper foil layer and an insulation protection layer successively from top down. The insulation protection layers are polyester films with a thickness of 0.08mm to 0.12mm. Strip-shaped bosses with heights of 0.05mm to 0.08mm are distributed on the films. Widths of the strip-shaped bosses and distances between the strip-shaped bosses are arranged based on using requirements of a flexible circuit board. The dual-layer flexible circuit board substrate provided by the utility model has advantages of being simple in manufacturing technique, controllable in bending state and comparatively good in heat dissipating performance.